Temp gauge not working

[Skater]

I have a 2006 xc70 and noticed tonight that my temperature gauge does not move at all anymore. There are no performance issues, engine performs normally, and no error messages. I figure it's either the temp sensor giving a faulty reading, or the thermostat is stuck preventing any heat from building up, or the gauge itself is fubared.
Any ideas or suggestions?
Thanks.

[Skater]

What I really need is the manual to test/replace suspect components. There is nothing on this in the resources section.
Any help is appreciated.

[Skater]

Does the engine management use the temperature sensor for anything? I am trying to get this fixed as soon as possible, but am I going to harm the engine driving it in this state? Does the computer think that the engine is still cold if the gauge hasn't moved?
Thanks

[Astro14]

OK -so there are three things to examine. 1. gauge itself 2. sender 3. thermostat. It could be that the engine is cold, that the sender is faulty, or that the gauge has failed.

I don't have the specs for the sender resistance, but how about the engine - is it running at a normal temp? I will bet that it is...the VDO series of gauges run 10 - 180 Ohms...I'll bet this one is about the same. You could check when the engine is cold and then when warm and see to what degree the resistance changes...

[Willy]

Does the engine management use the temperature sensor for anything?
Yes, it does:

The temperature of the engine coolant is required
so that the engine control module (ECM) can
regulate:
the injection period
the idle speed
the engine cooling fan (FC)
the ignition advance
engagement and disengagement of the A/C compressor
diagnostic functions.

Willy

[Skater]

Well, it magically started working again.:confused: I don't know if it's coincidence or not, but when it stopped working, it was really hot out, and when it started, the air temp had dropped. I'll monitor more closely too see if there is any relationship between air temp and working gauge.

[dsharp]

Make sure the sender is not corroded where it threads into the thermostat housing. The sender grounds through the housing.

[billr99]

Well, it magically started working again.:confused: I don't know if it's coincidence or not, but when it stopped working, it was really hot out, and when it started, the air temp had dropped. I'll monitor more closely too see if there is any relationship between air temp and working gauge.

It's possible that you have a DIM on the way out. Not much to do in that case other than to wait it out and see what goes out next. As a suggestion, you might want to do a bit of searching here on the subject just to prepare yourself.

Good luck,

Bill

[Skater]

Did a search, but couldn't find what a DIM is? Sounds bad though. I'm guessing it's the digital instrument module, or is that an amusing guess.

[Willy]

Your guess is spot on!
Willy