Instrument cluster and temp gauge

I have removed the instrument panel to see if I can fix the temperature gauge that hasn't worked for ages. Now that the car has aged… to perfection (1989, 19 year old) I believe that a working temp gauge is important.

Well, I have the panel in front of me at home and I have already identified the wire with an ohmmeter (it is the red/yellow one that goes from the temp sender in the engine block to lane n. 4 of the printed circuit).

Before taking the whole thing apart to isolate the temp gauge, what kind of testing can I do?

Simply sending 12 volts to the +ve lead of the temp gauge is enough?

TIA

Ben

You need a earth to the board , if bench testing you can use a 9 volt battery [type that go in smoke alarms etc] . Put earth terminal to Brown , connect + to red / yellow wire , guage if not faulty should rise slowly to 1/4 full .

If you need to do this on the car put a resistor in pos line to bring down the voltage or you may damage the board or guage .

chudd said

You need a earth to the board , if bench testing you can use a 9 volt battery [type the .

I have removed the gauge; it has three pins on the back:

this is the pict of the back of the instrument cluster:



What is A, B and C?

Many thanks,

Ben