Temp sender ?

[Hugh Mongus]

I have been trying to figure out why my temp gauge isn't working. It looks like the dark green wire from the sender comes through the firewall and into the ignition switch on the wiring diagram then back out to the dash plug, is this accurate? I don't have any dark green wires coming out of my ignition switch which makes me think this is my problem.

- I have tried grounding it out to see if the gauge moves but it doesn't.
- I have installed a new sender.

Thanks in advance.

[ray_mcavoy]

That dark green wire going to the ignition switch is only used on trucks with a warning light instead of a gauge. The ignition switch grounds that wire when cranking the engine. Grounding the wire completes the circuit and illuminates the warning light for a "bulb check".

With a gauge, grounding the dark green wire should cause the gauge to peg to the full hot side with the key on. If yours doesn't do that then you'll have to do some additional troubleshooting to make sure there isn't a break or bad connection somewhere in that dark green wire (or in the printed circuit/connections that connect it to the gauge). Also check to make sure the gauge is receiving power and has a good ground.