Westinghouse BJ425t playing-up

I've got a 20 year old Westinghouse BJ425t Fridge/Freezer. It recently iced-up and now I have to manually defrost it every 2 days or so.

Previously when it was working I would occasionally hear it performing the defrost function. I could hear drops of water hitting the heating element and making a hissing sound. At a guess I would say it did this once a day.

I was hoping that the defrost element was blown, because I would be able to replace that myself. I took it out but it is showing 120 ohm resistance so I think it is still good.

Sadly, immediately after I did the job of removing the defrost element, the fridge compartment no longer kept cool. I discovered the fan had been slighly fouled and now the fan appears to have failed completely (infinite ohms).

I have a new fan, but before I installed it I tried to figure out the important wiring and could make no sense of it.

I opened the back and took a look at the PCB.
There are a bunch of 7 thicker (eg power) wires from the PCB to the inside
brown, blue, green/yellow which presumable is active, neutral and earth
RED, PINK, WHITE, BLACK
The red and pink also come off the PCB and have a connector which is easily accessible at the back. What would this be?

Can someone please help me with a circuit diagram for this fridge, or a service manual for Westinghouse fridges circa 2003?

As I mentioned, there is a 2-pin service port at the rear of the control box.
One of you experts must know what that is for.

Not an expert.
Dont have a diagram.

But,

Maybe its a two speed motor.
Maybe its a safety circuit.
Maybe its a thermistor. ?

I take it the old fan is different from the new one?