Aftermarket Gauge Problem

[Wickham_1995]

I was just wondering if anyone could help me out here.

I bought a few gauges and i've got most working bar one, the coolant temperature gauge. It's fairly straight forward to wire up but still can't get it to work properly. There are four wires; positive, negative, gauge color and sensor. I've hooked the ground up, the positive is wired into my electric window switch so it gets power when i unlock the car and so fourth, the gauge color is hooked up to my trip computer so when parkers are on it gives it power to the light and my sensor is hooked up through an adapter that goes into the radiator to thermostat pipe.

When i wire all these up and give it power the gauge jumps straight up to 120c and doesnt do anything. If i unplug the sensor it goes back to 0c and light goes out and if i remove the positive it does the same thing.

Can anyone help me troubleshoot this problem? They are in a VS SII Berlina

Cheers

 

[Tasmaniak]

Have you tried a different sender?

 

[delcowizzid]

my sensor is hooked up through an adapter that goes into the radiator to thermostat pipe. this is probably your issue you need to earth the sensor

 

[Tasmaniak]

If this was the case, he would get no reading at all.

 

[VK SL 3800]

Thats not always the case, some gauges dont use the sender earth as the regulator of current through the bimetallic strip which controls the needle. Some dont use a bimetallic strip at all these days.
These types of gauge, without an earth the gauge will read full temp, pretty much opposite to a traditional gauge.

 

[Tasmaniak]

I hear what you're saying mate but given the fact that when he disconnects the sender it goes to 0. This would indicate that the sender is earthen and removing it is breaking the circuit.

 

[VK SL 3800]

hhhhmmmm i missed that bit, my bad.

 

[delcowizzid]

if theres 1 wire to the sensor it has to be earthed for sure .if the sensor is 2 wire would be a different story

 

[Tasmaniak]

if theres 1 wire to the sensor it has to be earthed for sure .if the sensor is 2 wire would be a different story

Exactly... so its earthen.