TK RD-II SR intermittent operation

[trammd]

Got an RD-11 SR that is starting to not power up the Microprocessor and cab mounted remote control. There is Power to the Interface board, all fuses good, Fuseable link good etc.
After changing all the units drive belts upon powering on the Microprocessor switch I would receive no power to the remote controller when trying to start the unit.
I cleaned the terminals on the corroded switch and the switch harness plug and thought that fixed it, Unit started and ran fine for a couple days. No alarms USC good etc.
Now I go to turn on the unit and same trouble. No power to cab controller.
Any ideas on how to further troubleshoot?
I checked interface board for any loose harness plugs etc but all looks good except for the fact that no power to processor and cab control when the switch is cycled on.
Any help is appreciated.

[seanf]

Do you still get power to the switch?
What happens when you bypass the switch?

[trammd]

Do you still get power to the switch?
What happens when you bypass the switch?

Yes, there is battery voltage at the switch. There are 5 terminals. The lower 2 have 12 volts.

[seanf]

Not sure if this is the right manual, but....
Theres a few pages of wiring diagrams for the RD-II 30 and RD-II 50 if you click through them.

https://www.manualslib.com/manual/21...age=128#manual

If the switch is as show on the diagrams then, it looks like when the switch is off you should get battery voltage at the terminals "2" and "2A".

When on the switch puts voltage from "2" out to "2N", and from "2A" out to "PL1".

Terminal "CHP" is described as a logic ground for the Thermoguard.

Looks like "2N" could be the main power supply for the Thermoguard, and the "PL1" as a sort of on signal?

[trammd]

Not sure if this is the right manual, but this is what I'm looking at.
Theres a few pages of wiring diagrams for the RD-II 30 and RD-II 50 if you click through them.

https://www.manualslib.com/manual/21...age=128#manual

If the switch is as show on the diagrams then, when the switch is off you should get battery voltage at the terminals "2" and "2A".

When on the switch puts voltage from "2" out to "2N", and from "2A" out to "PL1".

Terminal "CHP" is described as a logic ground for the Thermoguard.

Looks like "2N" could be the main power supply for the Thermoguard, and the "PL1" as a sort of on signal?

Thanks, This gives me something to check and yes this is the correct schematic for my unit.
I can back-probe the switch harness tomorrow and see if the switch functions as you describe.
Thanks again, I will let you know what I find....

[trammd]

Just to confirm...with the switch in the ON position I should measure battery voltage (12 Volts) BETWEEN
"2" to "2N" and also 12V BETWEEN "2A" to "PL1"
In other words I think you are saying I should read battery voltage when probing both wires (terminals).
One meter lead on "2" and other lead on "2N" should read 12V. (and also 2A to PL1)

Thanks again

[seanf]

-- When the switch is in the off position. --

With one of your meter probes on gound (chassis/earth/battery negative), and the other meter probe on either terminal "2" or "2A", I would expect to see 12v.

With one meter probe on ground, and the other probe on "CHP" or "PL1", I would expect to see near 0v.

With one probe on ground, and the other on "2N" I think youll see near 0v.

-- When the switch is in the on position. --

With one probe on ground, and the other on "2", "2A", "PL1" or "2N" I would expect youll see 12v.

"CHP" should still show near 0v.

Well thats what Im thinking anyway, if everything is as the diagrams and hasnt been messed with.

[trammd]

Thanks, I will let you know what I find....

[trammd]

-- When the switch is in the off position. --

With one of your meter probes on gound (chassis/earth/battery negative), and the other meter probe on either terminal "2" or "2A", I would expect to see 12v.

With one meter probe on ground, and the other probe on "CHP" or "PL1", I would expect to see near 0v.

With one probe on ground, and the other on "2N" I think youll see near 0v.

-- When the switch is in the on position. --

With one probe on ground, and the other on "2", "2A", "PL1" or "2N" I would expect youll see 12v.

"CHP" should still show near 0v.

Well thats what Im thinking anyway, if everything is as the diagrams and hasnt been messed with.

Okay, I was finally able to troubleshoot the switch.
It does check out exactly as you described above. so the switch is (was) functioning per design.
BUT HERE IS THE WEIRD PART:
when I initially checked the switch function with my meter I was receiving battery voltage (12.5V) at the proper terminals when actuating the switch and also at the logic board.

When I went to confirm my findings all of a sudden I am only getting 3.5 Volts at the switch test and logic board. I don't understand why it checked out good with full battery voltage one minute and then the next time I check everything is under volt at 3.5V!
I checked all the fusses again and they are all good.....
Please advise further, Thanks!

[trammd]

I just checked it again and it seems to be Intermittently receiving full 12V then alternates 3.5 to 4 volts. What the heck?

[trammd]

Okay...So I tied the Voltage drop with the switch function. When the switch is in the OFF position I get good battery voltage to the switch and interface board.
When the switch is Turned ON, Voltage immediately drops from 12V to 4 volts.

Is the Processor causing this Voltage Drop? and Why?

[seanf]

Does the voltage measured at the battery terminals drop as well, or is it just dropping on the Switch/Thermoguard circuit?

While your getting these low voltages, probe along the circuit(s) to see where the voltage is dropping. Put one probe on the negative of the battery, and then start with the other probe on the battery positive terminal, and then work you way toward the Thermoguard.

[trammd]

Does the voltage measured at the battery terminals drop as well, or is it just dropping on the Switch/Thermoguard circuit?

While your getting these low voltages, probe along the circuit(s) to see where the voltage is dropping. Put one probe on the negative of the battery, and then start with the other probe on the battery positive terminal, and then work you way toward the Thermoguard.

No, The voltage does NOT drop at the battery when turning the switch ON. Just dropping at the switch.
I did try a NEW Thermo king switch just in case the old one had some crazy internal resistance when "on" causing the voltage drop...but new switch does the same thing as the original one...

[trammd]

Can you tell from the schematic which wires feed the switch harness or maybe where I can begin checking where the voltage drop out is happening? Do you think a zapped or faulty Thermo-guard processer could cause these symptoms?
Thanks for all of your help!

[seanf]

If your measuring the low voltage at the switch, I would be thinking its probably a problem with resistance between the battery and the thermoguard.

That could be a number of things, the fuse link wire FLW, the 50A circuit breaker CB1, the 3A fuse F200, any of the wires themselves (corrosion or partial break), any of the crimp connections on the wires for the harness plugs, any other wire connections.

The only info on the diagrams, I put on the little drawing. Its not the best but...

[seanf]

It could also be that a wire has rubbed or melted and its in contact with another wire or something thats grounded.

[trammd]

Shouldn't that pop a fuse? F200 fuse is good. Where is the FLW? Is it the wire on the opposite side of the reefer unit on the terminals below the maintenance area access door? Also I have NEVER been able to locate CB1(50 amp breaker). where is it? Though I assume if this breaker was tripped I would not be getting battery voltage to the switch?
Keep in mind my unit uses the original Interface board service Part # 41-2145. It was used for initial production units through 2nd Quarter 2001.

[trammd]

Wow, Things just keep getting weirder! I was out checking fuses and I noticed all of a sudden with the switch ON I retained 12 Volts for once! I pressed the ON button and the cab controller lit up showing an alarm 61 (low batt voltage) I cleared the alarm and as soon as I did the controller went blank........you guessed it , low voltage again!
The Batteries are pretty new and I load tested them good. Maybe the next step is to remove all battery cables and the thermo king 12V main battery lead and clean all the terminals etc. (They look very clean)
I am stumped....

[seanf]

Fuses normally pop when theres a current more than their rating.
How much current flows depends on the resistances in the path, in the case of a rubbed or melted wire it might not be a good ground connection.

F200 fuse is good.
Do you mean that as in theres no voltage drop over it when current is flowing, or that its resistance measurement is low?

I'm not sure where or if your unit has FLW or CB1.
The breaker may not be tripped, it could just have a resistance to current flow, giving a voltage drop.

I've not worked on a TK RD-II SR for a long time, so I can only go by whats in that manual.

[trammd]

Yes I measure equal voltage to both sides of F200 (when current is flowing)

[seanf]

Yes I measure equal voltage to both sides of F200 (when current is flowing)

Ok, so with the switch "on" and one of your meter probes always connected to the battery negative terminal.

Take voltage measurements at:

-The battery positive terminal.
-Both sides of the fuse link wire (If you find one).
-Both sides of the CB1 breaker (if you find one).
-On the five switch harness terminals CHP, 2, 2A, 2N and PL1.
-Both sides of fuse F200.
-PL1 connection on the Thermoguard.
-2P connection on the Thermoguard.

[trammd]

Will do, Thanks

[trammd]

Okay here are my results (finally) with the switch "ON"

-The battery positive terminal. =12.98 Volts

-Both sides of the fuse link wire (If you find one). 12.98 V (only FLW I found and tested was on the opposite side of the reefer labeled "2")

-Both sides of the CB1 breaker (if you find one). Can NOT find a CB1 anywhere!

-On the five switch harness terminals CHP, 2, 2A, 2N and PL1. ALL measured 5.7Volts

-Both sides of fuse F200. Measured 5.7 Volts

-PL1 connection on the Thermoguard. Measured 5.7 Volts

-2P connection on the Thermoguard. Measured 5.7 Volts

Prior to testing I removed both battery's cleaned ALL terminals load tested great.(only one year old batteries) I also checked all grounds and reefer RD-II power supply ring terminals etc.

Here is the confusing part (To Me)
After initially powering up the switch after checking the wiring I was receiving 12.8 Volts with the switch "ON"!
thought I had this thing beat.
well, went to press the "on" button on the Cab mounted remote control panel and the screen lit up as designed (with no alarm codes!)
But before I had time to press the "enter" button to start reefer operation the screen went blank and ALL voltages at check points above dropped to 5.7 Volts. (except Battery and FLW positions remained at 12.9V)
All the control voltages dropped.
Sorry about the long winded reply but I am trying to be as specific as possible.
Any Further Ideas?
I think it it quite odd that initially the switch "ON" powered the Thermoguard and the remote cab control properly, but only for a couple of seconds after powering on the remote Cab control....

[seanf]

Okay here are my results (finally) with the switch "ON"

-The battery positive terminal. =12.98 Volts

-Both sides of the fuse link wire (If you find one). 12.98 V (only FLW I found and tested was on the opposite side of the reefer labeled "2")

-Both sides of the CB1 breaker (if you find one). Can NOT find a CB1 anywhere!

-On the five switch harness terminals CHP, 2, 2A, 2N and PL1. ALL measured 5.7Volts

-Both sides of fuse F200. Measured 5.7 Volts

-PL1 connection on the Thermoguard. Measured 5.7 Volts

-2P connection on the Thermoguard. Measured 5.7 Volts

Prior to testing I removed both battery's cleaned ALL terminals load tested great.(only one year old batteries) I also checked all grounds and reefer RD-II power supply ring terminals etc.

Here is the confusing part (To Me)
After initially powering up the switch after checking the wiring I was receiving 12.8 Volts with the switch "ON"!
thought I had this thing beat.
well, went to press the "on" button on the Cab mounted remote control panel and the screen lit up as designed (with no alarm codes!)
But before I had time to press the "enter" button to start reefer operation the screen went blank and ALL voltages at check points above dropped to 5.7 Volts. (except Battery and FLW positions remained at 12.9V)
All the control voltages dropped.
Sorry about the long winded reply but I am trying to be as specific as possible.
Any Further Ideas?
I think it it quite odd that initially the switch "ON" powered the Thermoguard and the remote cab control properly, but only for a couple of seconds after powering on the remote Cab control....

On the switch harness terminal CHP I would have expected you to have got 0V (maybe worth doube checking?). The other four 2, 2A, 2N, PL1 showing the 5.7V sounds sort of right, not the 12.98V you want but atleast their consistant with each other.

It sounds like you have a voltage drop between the fuse link wire and the switch. That could be because of things like a partially broken wire, corrosion in the wire, corrosion on a terminal connection, loose terminal connection... ect.

When the Thermoguard and cab control initially power up their probably drawing very low current, and the damaged circuit can handle it. Once the system moves into its next stage its going to draw more current and the damaged wire/corrosion ect... will show up as a resistance to the higher current flow.



I would guess the damage/corrosion/ect.. is located between, the outlet of fuse link wire and the point where the circuit splits into two (where it goes off to the switch harness terminals 2 and 2A).

[seanf]

Editted 29/09 with additional red text, see post #42 also.

Damage/corrosion to wires isnt always visable, it could be under the wire insulation.

--------
*****Dont do this.
From all the things your saying, I would probably try putting some fused bypass/jumper wires from the battery to the two switch inlet terminals, and see what that does. It would create the same circuit, just with wire you know is good. To give power to the Thermoguard only, and not to try running the unit with.

(If you run the unit, it could back feed current to the other parts of ciruits 2 and 2A, possibly pulling current through parts of the circuit that are not design to take that much. So the Thermoguard should have been disconnected from the rest of circuits 2 and 2A.)

One wire from the battery to a 50A fuse, then from the fuse to terminal 2A on the switch.

Another wire from the battery to a 3A fuse, then from the fuse to terminal 2 on the switch.

Do not try this without using fuses, or if you are unsure which terminals are which on the switch.



*****
----------

Maybe you are at the point where a Thermoking tech would be the best option, thats up to you.

[trammd]

Thanks for all of your insight and wiring diagrams. (the diagrams are really helpful!)
What you have suggested is a simple enough work around to re-route the original harnesses power feed(s) to the switch.
I will go ahead and try using the jumpers as suggested from the battery to the switch power feeds 2A and 2. (fused of course as you have advised)
Can't hurt to try this. If anything it will prove (or disprove) any issue with the factory harness power feeds to the switch.
Thanks again and I will report back!

[trammd]

IT WORKED!

So tentatively I am calling this fully troubleshot thanks to you.
After replacing the Thermokings power switch power feeds with fused feeds direct from the battery all is working.

Okay here are my results (finally) with the switch "ON" and power feeds jumped to the Battery.

-The battery positive terminal. =12.98 Volts

-Both sides of the fuse link wire (If you find one). 12.98 V (only FLW I found and tested was on the opposite side of the reefer labeled "2")

-Both sides of the CB1 breaker (if you find one). Can NOT find a CB1 anywhere!

-On the five switch harness terminals CHP ZERO VOLTS, 2, 2A, 2N and PL1. ALL measured 12.8 Volts

-Both sides of fuse F200. Measured 12.8 Volts

-PL1 connection on the Thermoguard. Measured 12.8 Volts

-2P connection on the Thermoguard. Measured 12.8 Volts

I ran the reefer for 30 Minutes, shut it down and followed with a Unit Self Check (NO CODES)[/I]

Since this is a static reefer for me (Not on the road) Would it be okay to keep the wires bypassed rather than try to chase the mystery corrosion or break in the factory harness?
I am using quality heavy wires and fused protection. I will re-route my new harness to the switch up the back of the cab as per the factory one.
Thanks Again. I hope this is finally fixed for good! -Duane

[trammd]

SPOKE TOO SOON

Third try at start up after 2 successful tries and I get a shut down alarm code 35 (On/Run relay circuit)
K7 run relay is fine. (check with known good one)
Fuse F305 checks good

So now Thermoguard wire 2P is zero volts with switch is on. (All others still read battery voltage, PL1,2A,2,2N etc)

wire 2N still outputting 12.8 Volts from the switch when ON. F220 Fuse is GOOD. (both sides of fuse measure 12.8V to ground) so why does 2P at the thermoguard have 0V????? and no power up of the in Cab control (blank when "on" is pressed.)
I am soooooo confused.

[trammd]

OKAY, 2P to Thermo-Guard is receiving battery voltage. (I wasn't making good contact with my wire piercing lead)
Still though... reapeated Alarm 35. when I clear it I hear what i beleive is a relay. then I try to restart and always get the #35 Shut down alarm.

so now the Voltage drop from the switch is remedied but now this new issue...
Thoughts?

[trammd]

Oops, already did this.( Running the unit with the switch jumpers)and the unit did run a couple times until throwing alarm 35.(On the 3rd restart )See my notes.
Thanks, and yes my board is the same original interface board shown. I will try the P5 test when I get to the shop.
Thanks again

[trammd]

If you run the unit, it could back feed current to the other parts of ciruits 2 and 2A, possibly pulling current through parts of the circuit that are not design to take that much. So the Thermoguard should have been disconnected from the rest of circuits 2 and 2A.)

If I removed the factory wires 2 and 2A from the switch harness plug and replaced them with the jumpers how could it backfeed to the factory harness if they were removed and out of the circuit when testing?

[seanf]

If you run the unit, it could back feed current to the other parts of ciruits 2 and 2A, possibly pulling current through parts of the circuit that are not design to take that much. So the Thermoguard should have been disconnected from the rest of circuits 2 and 2A.)

If I removed the factory wires 2 and 2A from the switch harness plug and replaced them with the jumpers how could it backfeed to the factory harness if they were removed and out of the circuit when testing?

As your saying it couldn't. I assumed wrongly that you had added jumpers onto the terminals without removing the harness wires, like on my silly drawing, sorry.

Thats good then, running the unit shouldnt have caused any problems. Just gave the Thermoguard and on/run relay coil a solid power supply.

[trammd]

Okay here are some results.....

I removed the battery feed from the FLW and capped it (killing power to the board)

I removed both wires labeled "2" from the boards terminal P5

I attached my Fused 12V Jumper wire direct from the Batt. to the board Term. P5

The result is now I have NO voltage drop after turning switch on.
and I have battery voltage (12.8) to thermoguard wire PL1, and to wire 2P at the thermoguard.
My cab controller DID power on and after I cleared the alarm code 35 the reefer did complete it's start up cycle and ran. This is with both factory "2" wires removed from P5 at the board.

Here is the Odd thing, Charging voltage on the Cab Control LCD reads at 14.9-15.1 Volts. (I get this reading at the Battery, The alternator terminal and at all controls while the unit is running.) This is mucher higher than this unit used to run at. (Usually 13.2-13.6Volts while running previously)

Do one of those factory two "#2" wires I removed from the P5 terminal go to the alternator and if so why would my alternator output increase this much?

Not sure how to proceed?
Thanks

[seanf]

Id need to have a look into it, but probably won't have time until the weekend.
Hopefully one of the other forum members can help before then.

[trammd]

Thanks NO hurry as I am entering my Off Season so don't need the reefer until next Spring. Thanks again!

[seanf]

The fused jumper wires are only really to get power to the Thermoguard itself, for testing. I'm guessing the voltage drop on circuit 2 and/or 2A are giving you other problems.

Hopefully your units board looks like this one in the manual on page 129?

https://www.manualslib.com/manual/21...age=129#manual



If so, it might be worth trying a few tests.

First remove the jumper wires.
And then with one of your test meters probes always connected to the negative battery terminal.

With the switch "on", check what voltage you get at:

-Terminal P5 on the board.
-Terminal P7 on the board.
-Terminal P13 on the board.
-Terminal 2 on the switch.
-Terminal 2A on the switch.

The manual shows there are two wire no. "2 "'s, going from the FLW through the "Engine Harness" to the board.
And the one wire no. "2A", going from the alternator through the "Condenser Harness" to the board.

[trammd]

Okay here are the results:
I removed my jumper wires and all reading taking measuring from battery ground.

Switch "ON"

Term P5 = 5.5V
Term P7 = 5.5V
Term P13 = 5.5V
Term 2 at switch = 5.5V
Term 2A at switch = 5.5V

With switch "OFF" I measure 12.8 Volts at all measured teminals.

The odd thing is it took 20 or so seconds for the voltage to drop after the switch is turned "ON" initially (the first time I tried).
Then after the intial switch "ON" the cycle of the switch and the voltage drop responded immediatly to the switch position.

[seanf]

It sounds like the voltage drop is on the wire "2" on the engine harness itself.
You could try using a jumper wire from the outlet of the FLW, to a 50A fuse, then from the fuse to the terminal P5 on the board.

[trammd]

I can try that tomorrow, so to be clear remove the factory "2" wire from terminal P5 before I attached my fused 50amp jumper wire to it?

[trammd]

Does jumping direct from battery+ to P5 do the same thing?

[seanf]

You can remove wire "2" from P5 if you like, but the wire will still be connected to the battery positive unless you disconnect it from FLW, so dont short it out.
The manual shows three wires coming off FLW, two wires numbered "2" and one sense wire going to the alternator.

[seanf]

Yer going from the battery is near enough the same thing. It was just to put that FLW inline as well for safety. Make sure you use a fuse on the jumper wire though incase something goes wrong.

[trammd]

Okay thanks. I will try to jumper (fused) 12V from Battery to P5.

Is P5 the main power suppy to the board?
If I get the same voltage drop results after jumping 12V to P5 does that mean the engine harness is good and the problem could be after the relay board or in its circuitry?

Could a faulty alternator cause these issues I am having? This all started originally after I had the alternator out during a belt change. It's the ONLY thing wiring wise that has changed. although the unit has run since that time and shows the alternator charging so I guess probably not? The alternator is original to the unit.

[seanf]

I can only really go by whats in this manual. And assume your unit is the same?

https://www.manualslib.com/manual/2123882/Thermo-King-Rd-Ii-Sr-30.html?page=129#manual

On page 129, it gives a physical layout of the wiring and board. You can zoom in on the drawing by pressing the little magnifying glass on the top right hand corner of the drawing (on my computer anyway).

If yours is the same, it looks like P5 is the main power supply to the board, with the wiring connection located on the left hand side next to fuse F310. The manual seems to show that there are two number "2" wires connected at P5.

--->> If your unsure of the wiring I would not try the jumper wire tests.

From your measurements it seem like you have a voltage drop on circuit "2" before it gets to the board.
Because your only getting the 5.5V at P5, but you still have 12V at the outlet of FLW, it makes me think there is a problem with the circuit "2" from FLW to P5.
Otherwise I would have thought youd see 12V at P5, as it looks to be just a wire. (maybe theres other connections along that path?)

With a jumper to P5 you still get voltage drops, then I'd be thinking youve got another fault to find.

What your saying dosnt make me think the alternator is giving you problems, but I guess you could always disconnect the alternator and try switching on the unit, but not run it.



.
.
-----------------------------------
.
A side note:
After giving more time to looking at the physical layout of the wiring on page 129 of the manual, and not just looking at the wiring schematic. I've added text in red to post #26, and I will leave the original text to show my errors.

[trammd]

Yeah I de-pinned 2 and 2A from the switch harness plug and covered them since they were still live, then re-pinned the harness plug with my fused jumper leads.

[seanf]

You might have disconnected the sense wire that goes to the alternator voltage reg.


The schematic shows the "2" wire(s) and alternator sense wire are at the outlet of the FLW.

The physical layout diagram shows three wires at the outlet of the FLW, one sense wire and two "2" wires. Both "2" wire look to go to the P5 terminal on the board.

So youll need battery connected to FLW, which then feeds the sense wire. How many wires do you have at the outlet of FLW?

[trammd]

I will get you a photo....hold on

[trammd]

The reefer passed a Unit Self Check and has been running for about an hour with the P5 jumped.
Alternator charging voltage when read on the in cab controller LCD has dropped to 14.5 to 14.6 Volts. (acceptable)
Still reading 15 Volts at battery when charging. (PL1 and 2P at the thermoguard are at 14.5 Volts - mirrors the cab readout)

Kinda scratching my head. It's running but I don't trust it

[seanf]

Upload it to somewhere like Flickr.com and then post a link.

[trammd]

low res 2R (1).jpg

low res1 (1).jpg

See the above photos. The fusible link only had the one large guage battery feed (8 Gauge?) mounted to the left stud side of it. (It is removed in the photo as per my testing- you can see the white wire taped out of the way in the second photo.)
There is an access cover under the RD-II... maybe the feed wires (alt., etc are located on the back of the FLW stud right side. (not visible from the access door side)?