Is is possible to fix a failed Porsche 986 Temp gauge?

At least possible for cheaper than selling it and buying another one that the gauges work. 

2000 2.7 base model.

It has worked intermittently since I bought it, sometimes it reads properly, sometimes about half what it should actually read, and sometimes at all.  If you turn the car off and back on again sometimes that will make it read properly for a while.  I have changed all the temp sensors except the one that is also an oil level sensor on top of the engine and that did nothing.  The temp reads correctly with an obd2 scanner plugged in, but I had the idea of using a scan gauge and just leaving it plugged in and the scan gauge doesn't get enough power from the port to turn on. 

I suspect it's probably not worth the cost to fix, but it would be nice to actually be able to tell if it ever gets too hot.  The car has very high mileage for a Boxster though, and is 25 years old and has a lot of other electrical problems so I somewhat think the wiring is just wearing out.

Checking for a bad ground is free. I would start there. 

Given that the instrument cluster gets that data through CAN, if the other gauges are working correctly then the fault is internal to the instrument cluster assembly.

Being unfamiliar with this model, I couldn't tell you if things are replaceable piecemeal or if the whole assembly needs to be replaced.  The most I would do is pull it apart and carefully inspect the solder connections on the circuit board for signs of cold cracking, which can be reflowed.

Pete. (l33t FS) said:

Given that the instrument cluster gets that data through CAN, if the other gauges are working correctly then the fault is internal to the instrument cluster assembly.

Being unfamiliar with this model, I couldn't tell you if things are replaceable piecemeal or if the whole assembly needs to be replaced.  The most I would do is pull it apart and carefully inspect the solder connections on the circuit board for signs of cold cracking, which can be reflowed.

 

Unless you have a screen instead of gauges, the gauges will be replaceable piecemeal. The question is how many tools you need. 

And I would definitely suspect a faulty solder joint when just one gauge works just some of the time.