What to use it for:
 

In a 67-72 truck with full gauges, the instrument panel has a bulb in the temperature hole and it's wired through the circuit board but there is no wire feeding it in the bulk connector.

So has anyone hooked it up to something to use it?

I'm thinking maybe some other kind of light but it would be awfully bright as it is now.

After reading this link worth of info I'm not sure it's all right.:chevy:

http://67-72chevytrucks.com/vboard/s...d.php?t=762120

I hooked my cluster up to my 12 volt converter box and the temp light will not come on unless I put power to only the #5 terminal. This terminal is blank in a truck cluster that has gauges. If I hook it up to all the other lights it want come on either.
I have also noticed the #1 wire is blue instead of black/brown. This could be a year thing, not sure.
Anyway I guess I'll leave it as is for now.

Re: What to use it for:
 

You could wire it up to a temperature switch on the engine and have a functional temperature warning light. Leave the wiring for the temp gauge as-is and you'd have both a light & gauge. Similarly, you could wire it up to an oil pressure switch on the engine and have both an oil pressure gauge & warning light ... you'd probably want to change the plastic cover/filter so it reads "oil" instead of "temp" though. Or any other light you want it to be by simply changing the cover/filter and wiring it up to the appropriate switch.

If the bulb currently installed at that location is a #168, changing it out for a #194 should reduce the brightness a little. Adding a layer (or layers) of thin semitransparent tinted plastic under the lens filter should also dim it down a little if needed.


To bench test the temperature light on the cluster, you should apply +12V to pin 3 of the cluster connector (pink wire that also feeds power to the fuel gauge). Then ground pin #5 (no wire) to illuminate the temperature light.

The wire color difference on #1 is most likely the result of a previous owner having converted your truck from warning lights to a gauge cluster. They likely re-purposed the existing dark blue (oil light) wire that was originally in that location and no longer needed with the gauges. Or if your truck came from the factory with gauges, it might have had a dash harness swap at some point in the past and someone re-configured a warning light harness to work with the gauges, again, re-purposing that existing dark blue oil light wire.