temp gauge stoped working

[craigH]

Hi all, my temp gauge has stoped showing the correct temp, it stays either all the way to the left or moves just enough to cover the C. I have had the dash off and all the wires to the circuit board behind the gauge look to be connected, I have changed the sender for a new one, I have tried to earth the wire first at the sender attachment then further up the wire with the ignition on but the swith didnt move, I think that not enough or no power is getting to the switch, I have checked all the fuzes I can find and all seem ok, but now Im not sure how to proceed? I have a aux temp gauge which Im going to run from the radiator top pipe but want the stock one to work!! Any suggestions are appreciated, thanks

[BUSHWHACKER]

Have you checked for any airlocks in the cooling system, seeing that you've had the top hose off and the sender out.

[craigH]

thanks for a quick reply! I havnt instaled the aux gauge yet, doing it this wkend, the prob started without me touching the cooling system, changed the sender when the gauge stoped working. Coolant is still circulating, just not getting a reading. I jump started a car the other day, could that have affected the ECU to cause this?

[BUSHWHACKER]

The temp gauge sender is independant of the ECU.
Do the heaters still get hot?
There could be some fraying or breaking down of the wire due to engine heat causing a weak signal to the gauge.

The engine sensor wires enter the cabin in the corner behind the power steering reservoir and go down to two multiplugs that are behind the ECU, which is behind the kick panel.

You could try a new length of wire from the sender to to multiplug and see if the gauge works. Yellow wire with blue stripe I think. Time to get the multimeter out anyway.

[craigH]

ok thank, I'll get the kick panel off and have a look, the heaters do seem less hot almost as if the heat is coming from the hot coolant passing through instead of getting heated by the heater

[craigH]

problem solved! Found an old post saying to check the thermostat, got the thermostat out and the jiggle valve had been caught holding the stat open about 1/4in. changed it for a nip parts one. Last time I buy from milners thats twice the "cheaper" option has seen me off.