sharky47

As soon as you turn the power on with the key, the temp gauge goes full hot. I am leaning to a bad gauge because I just replaced the whole cluster with a used unit to fix a bad tach - and the temp gauge worked before I did this. Is there any easy trouble shooting work I can do, or should I just go ahead and swap in the old gauge (I hate pulling the cluster.....) TIA!

Epic2112

If I remember correctly, the more voltage that goes through that circuit, the higher the gauge will read. So, the temp. sender is less and less resistant as the car heats up, letting more electricity through to the gauge, which moves the needle. As such, if you have a short somewhere that removes the temp. sender from the circuit and lets electricity pass through without resistance the gauge will peg.

You should check the voltage coming to the gauge with the car cold, thyen let the car warm up and check again. If it's the same, you have either a wiring problem or a temp sender problem.

Dal Heger

Wiring problem or bad gauge. When you ground the contact to the block the gauge reads full hot. Check the resistance of the gauge, if that checks out fine then you have a grounded wire.

Dal.

Yummybud924

well I had a 78 924 and it has the same dash and gauges and when I removed my dash then put it back together the temp would read red when the igntion was on and it was a bad ground I believe.

Keithr726

Something similar used to happen in my 83. It stop after I cleaned the wires going to the sender.

924RACR

Yeah, short to ground will peg it. Check your shorts!

sharky47

Haha, we'll tinker with it tonight - the only thing we changed was the gauge, but we did take it in and out several times - so who knows........

dean944

I had same problem when I purchased a used tach off ebay. I believe the tach was for an auto 944 b/c no shift lite. Anyway, with the ground wire hooked to the tach, the temp gauge pegged immediately.

Check to make sure your new guage is the correct one, if so Id say it has a ground where it should't.

I have a early temp/gas guage I sell you if you need it.

I also have a speedo unit but the odom gear is worn. Good for parts though.

sharky47

Where did you end up putting that ground?

dean944

Well I wound up sourcing a tach for a 5 spd (with shift lite).

The auto tach didn't have the male term for the ground. When I grounded it at tach chassis is when temp went full hot immediately. I thought this was very strange but didn't have the brain power to troubleshoot it at the time.

I still have the auto tach too if anyone has a use for it. I don't know why anyone would want a 944 auto. Even my wife doesn't like sports cars in auto.