Temperature Gauge Fault

[tomwillans]

My temp gauge that was working fine is now reading zero all the time. I have checked the voltages 12V supply ok and sender 6-7V. The sender voltage gradually increases as the engine warms up. This therefore looks like the gauge. A fellow club memeber has offered to bring in another temp gauge for testing.

 

Is it possible to test/fix a gauge or is the simplest thing to go out and buy a new gauge?

 

Thanks

[Sea Dog]

Well, you've proven your sender is responding, presumably properly, to increasing temp so it's either your wiring or the gauge. If you're content with the wiring and connections, it's probably new gauge time already. However, you might as well try your mate's gauge if it's the same as yours or is compatible with your sender - if it works, yours is duff and you might aswell see if you can take it apart and fix it. Replacement is probably the easiest and cheapest route to success though.

 

 

 

Edited to finish what I was trying to say!

Edited May 9, 2016 by Sea Dog

[tomwillans]

Ok. Thanks sea dog. Pretty sure the connections are ok but I assumed if the voltages measured were ok then the wiring was ok. Bit of an undocumented birds nest behind the control panel which I aim toi document for my own sanity.

[Iain_S]

If the wire to the sender is disconnected, and touched to earth/negative the gauge should go to maximum. (Done with engine stopped, but key in "run" position)

 

I'm a bit surprised the voltage at the sender increases as the engine warms up, though. I'd expect it to decrease as the sender resistance decreases. How was it measured?

[tomwillans]

I measured it using a voltmeter between common and sender. I will recheck it. Sounds like a useful check that the gauge can go to maximum. Thanks.

[tomwillans]

Well I have checked the wiring and earthed the sender in order to max out the gauge. No response so I have ordered a new gauge. In the process I found some extra loose connections hanging on by a thread do fixed that. I will let you know how I get on. Next job the engine compartment etc....