temp gauge not working - 1976 c10 350

[aleighs1990]

On my 76 c10, the only gauge that that does not work is the temp gauge. I don't know much about these old trucks, it's actually my first pre-90s vehicle. Where do i start, and what all do i check? Is there maybe a common problem/solution?

[bd]

Assuming factory gauges...

The temperature gauge wire is dark green and plugs into its sender on the driver side cylinder head directly between the 1st and 2nd spark plugs.  Verify that the wire is actually connected to the sender.

With ignition switched ON and the temp sender unplugged, the gauge should read cold.  With the green temp gauge wire grounded to bare metal, the gauge should read hot or above.  Try that and report back.

[aleighs1990]

yes, all gauges are factory. i ran the test above, everything did as you said it should. whether the wire is connected to or disconnected from the sender, the gauge stays cold. when the wire is grounded, gauge pegs as far past hot as it can

[bd]

This is a grassroots approach, but if the engine is heating to ~195 (the temperature of a stock thermostat), replace the temp sender.  Be sure to purchase a sender for a gauge and not a light.

[bd]

Read through Correct temperature sender and connector, then PM Captkaos for the replacement part(s) you need.