How to test gauges (also on BBS912)

[hbhaller]

How can one test whether or not a combo temp-fuel gauge works?

I've got a '66 912 that has been converted to a five gauge. I've aquired the correct gauges from Parts Heaven, but I'm having trouble with the Combo gauge. When I bought the car, the far left was fuel, the 2nd from left was temp. The old temp-only guage works fine, but when I hook up the wires to the temp gauge side of the newly acquired combo gauge, I get nothing. I've got the wiring diagram and I think I've got it right, but I'm not sure.


By the way, I took the gauge apart a bit to clean it up, and I noticed at the top of the temp gauge insert that there are calibration numbers, in celsius. They are hidden when the insert is placed into the gauge. You can't seem them too well in the photo, but the first mark (from the left) is 66 degrees, the second from left is 120 (that's about half way), the third is 138, the next is 146 (maybe, it is not quite that clear, right at the red line) and the last is, I thing is 151. I have no idea what those work out to be in Farenheit.....

Brandon 'wasting time and trying not to fry my gauges' Haller
Fairfax Co. VA

[Morrie]

When the temp guage is wired properly and the sender is unplugged, the guage should peg on hot. If you ground the sender wire, it pegs on cold. This should narrow down your search.

Morrie