Temperature Gauge

[Kelley W King]

My 69 temp gauge does not work. It is a console gauge. I have tryed two sending units. When the ignition is turned on it moves and when you ground the sender wire to the engine it moves to hot but does not work.

[mikefam]

If you are disconnecting the wire from the sending unit and grounding it  and the gauge responds my moving to full scale then it sounds like the gauge and wiring is fine and the problem is with the sending unit. Maybe it is not the correct sending unit for your gauge.

Mike.

[JohnZ]

With the key "on", if the gauge pegs to full cold with the wire disconnected from the sender and pegs to full hot with the wire grounded to the engine, the gauge and wiring are OK.

[Kelley W King]

Tryed all of the above with no luck. Any chance it is the resister?

[Mark]

Whats it do, or not do when you ground, or open circuit the wire to the sender?

[Kelley W King]

It does exactly what Johnz comment says it should do. Key on wire off all the way cold, key on wire grounded to block all the hot.

[Mark]

You didn't use teflon tape, or plumbers dope, when you installed the sender did you?  If so take it off, the sender has to be grounded to the block to work.

If not then its either the wrong model sender, or its a temperature switch, not a sender.

Whats the resistance of the sender measure, between the centerpost on the sender and the block when the engine is cold, and what is it when the engine is hot?

[Stingr69]

I would be concerned that you were given an "idiot light" sender both times, rather than a proper "guage" sender.

-Mark.

[Kelley W King]

Problem found. Ground from gauge housing to transmission tunnel was not connected. Problem discovered when turning on the gauge cluster lights caused the temp gauge to move to hot. All 3 other guages worked fine without the chassis ground but not the temp gauge.