Hi. Thanks for having me onboard. I need some help with my Fiat Ducato 2.8td, 05 plate. My temp guage is erratic. It goes just over halfway with ignition on and engine not running. I have tested the plug with ignition on and the sensor reads 4.7v on one terminal & 9.8v on the other. I'm convinced it maybe an electrical/ earth problem.
Hoping somebody knows what the problem could be

Thanks

Hi. And welcome.

Sounds like an earth issue

SEARCH on here is great.. you may well find similar threads

Charlie

Thanks Charlie, but you're the only person to have replied at this moment in time. Hope somebody can shed some light on this issue

Hi
A very common arrangement is for there to be two temperature senders, one for the gauge and a separate one for the engine management. They are pretty simple internally, being a thermistor, i.e. a special resistor which changes value with changing temperature. The two senders may be combined into a single unit, which will have two connections plus a common ground connection. It's likely (but not certain) that both senders will be nominally the same resistance at any given temperature. The simplest check is to ensure that the connections to it (as with any connectors in the engine bay) are clean of corrosion on the mating surfaces and tight. The next thing to try is disconnecting the wires, switching on the ignition for say 20 seconds and then off again. Then reconnect the wires. This may be enough to restore proper operation of the cluster. Beyond that, you may have to try a new sender.

Some things that have worked in the past.

Disconnect at dashboard and reconnect.
Add another earth lead in engine bay.
Replace sender unit at front of engine

Jev88 said:

Some things that have worked in the past.

Disconnect at dashboard and reconnect.
Add another earth lead in engine bay.
Replace sender unit at front of engine

Click to expand...

I have tried both apart from adding an extra earth lead in the engine bay. That's my next on my list. I will update after it's done. Thanks Jev.

Have you replaced Thermostat and sender unit?

All sorted and working fine now. I changed the other sensor adjacent to the one that sends the signal to the temp gauge and it's working great now. Thanks for all the help ???