Jake1982

Hello

First post on here....

My 82 - 4.5 Euro temperature gauge is being a pain in the ***! Please can anyone help?

When I turn the ignition on, the needle flicks up (as do all the others) but it doesn't move at all from there (all other gauges work).

Here's what I have tested so far....

-Have earthed the sender to gauge wire and needle goes to top of gauge (so assume the gauge is ok??)

- Voltage at the temp sensor from the gauge is around 6 volts. I have removed the sensor, earthed it and heated up the end of the sensor while the connected to a multimeter and the voltage decreases but the gauge needle still doesn't move???

Please can anyone else help? It's soooo frustrating.

Cheers
Jake

LFA

Got the same problem on my 91 GT and posted it on the forum yesterday, tried similar solutions to yours, check out the comments ı received yesterday. Mine is a 91 GT with digital cluster, the only difference is; my temp needle does not move even a bit on ignition, it stays where it is left corner. Searching if this could be a ground issue( water bridge powder coated) before uninstalling the cluster.

Jake1982

Hi LFA, I read that actually. Sounds like it isn't getting any power or a ground issue like you say?? Bloody annoying!!! Hopefully someone with lots of Porsche knowledge will help us out :-)

Mrmerlin

Jake cut off the connectors and then add a drop of deoxit to the wire,
then crimp on new connectors,
they are different sized, do one wire at a time
also install a new temp sensor and sealing washer

Jake1982

Hi Mrmerlin

Thanks for the help. I have a spare temp sensor and have the dials out of the car so am going to build a rig tonight and test it with 'new' wires. Will see if I can at least get the dial working out of the car, hopefully this will help me narrow down the issue!!

Do you have any idea how long the temp sensors last? I am pretty sure the one in the car is quite new??

Cheers again, will update with test results later

hacker-pschorr

The temp gauge in my 87 doesn't work until I give the pod a good smack (not kidding) so at least I'm 99.9% sure the problem is in the gauge cluster.

Jake1982

Ha ha cheers Hacker, I will give it a whack later and see what happens!!!

Jake1982

UPDATE!

So I took the dials, battery and temp sensor and rigged up a test unit. The dial didn't move and voltage remained constant at the temp sensor. Swapped the temp sensor with a small bulb I found lying around, the bulb lit and the temp sensor moved!

Obviously the issue lies within the temp sensor and/or the earthing of it.

Does anyone know the correct way to test the resistance of the temp sensor please? Is it one pin to ground?

Cheers again for everyones help

Mrmerlin

Jake replace the new part with a fresh one, OR install the old part

Jake1982

Hi MrMerlin

So had another temp sensor at the bottom of my box of 928 bits and tried that one, it worked. The gauge went up and down in line with the heat.

SO clearly temp sensor is knackered, bit surprised as it is a fairly new one from Porsche.

ANyway looks like it is sorted now

Cheers for help

928Collector

Gentlemen:

I've reviewed the prior comments and done the following:
-Temp 1 sensor replaced
-Temp 2 sensor replaced
Connections Deoxit.
Fuses checked.
Anti freeze put in

The Temp gauge flickers but then does nothing even after driving. All the other gauges work.
Any help much appreciated. .

Mrmerlin

classic please post pictures of the sensors you have installed with the wires connected.
AND a picture of the 14 pin connector

928Collector

Thanks. Please see below. On the 14 pin connector, i've pulled the male/female parts and Deoxit both parts. All the other gauges on my instrument cluster work - only the Temperature Gauge doesn't fully work. Some other forum comments said it whas the Thermo II(red arrow) that sends the signal to the gauge? and that Temp I and II sensors go bad so i replaced both. What picture did you need of the 14 pin connector?


I've replaced the Thermo 1 (blue arrow) and the Thermo 2 (red arrow) with crush washers but the Temperate Gauge on the instrument cluster flickers on start up but doesn't show the temperature when driving.

Mrmerlin

OK does the red warning lamp for the temp gauge come on when you turn the key to run without starting the engine?

Reason I wanted pictures is to acertain the condition of the machine we are working on.
NOTE its common for the wire insulation to fall off the wires that go into the engine side of the 14 pin connector, this can let them short out.

To test the gauge
With a helper turn the key to run take one wire off the temp sensor and touch the wire to ground the gauge should peg.
NOTE the other wire should make the warning light come on,
but it will already be on since the engine has not started .

So you would test the light wire with the engine running.

NOTE this is only a brief touch to ground you can melt the internals of the gauge windings if the wire is held for longer than about 30 seconds.
NOTE it could be possible someone miswired the gauge sender and cooked the gauge. The test I suggested should let you know if the gauge is working

GUMBALL

I just had a similar problem - when driving, the odd time the gauge needle would go to "full hot" (first time nearly caused a major cardiac event) then return to "normal"
I checked the wiring connections, checked the gauge, finally replaced the temp sender. Problem solved.