No power at Temperature sensor

[brooksman9]

Trying to troubleshoot this temp gauge on my 86 K10. I have no power at the wire going tot the sender. On my 86 C10 I do. Where does this power come from. I looked through the wiring diagrams but cannot find the actual gauge on it. Gauge on the dash reads about halfway between cold and warm and never moves. Does not go back to 0 when off. Any ideas? Thanks

 

[Rickf]

Any other gauges acting up? Fuses test ok?

 

[brooksman9]

All other gauges good. Is there a fuse specifically for the temperature gauge and sensor?

 

[Ricko1966]

You shouldn't have voltage at the temp sender wire.You should be able to short the wire to ground and peg the gauge though.

 

[brooksman9]

I assumed it did as test light came on with the C10 and not the K10. C10 gauge works. K10 gauge never moves from about 150.

 

[Ricko1966]

I assumed it did as test light came on with the C10 and not the K10. C10 gauge works. K10 gauge never moves from about 150.

Short the sender wire to ground,see if the gauge pegs.

 

[brooksman9]

Nope. Doesn't move. Does the gauge feed through the printed circuit board or is the wiring separate because I did see a couple of disconnected wires behind the dash in that vicinity. maybe tannish colored or light green. Hard to tell. Also color blind. lol.

 

[brooksman9]

Also, all electronic stuff is gone. Nothing computer controlled anymore. Not well versed on what any of that did in 86 or if anything is even still hooked up to it.

 

[Ricko1966]

I'm not well enough versed on these trucks to guide you on the gauges,without pulling a cluster out and investigating,but too busy,and not motivated enough. I would assume it pulls power and ground from the printed circuit and a separate ground as the variable ground from the sensor.

 

[RustyPile]

Trying to troubleshoot this temp gauge on my 86 K10. I have no power at the wire going tot the sender. On my 86 C10 I do. Where does this power come from. I looked through the wiring diagrams but cannot find the actual gauge on it. Gauge on the dash reads about halfway between cold and warm and never moves. Does not go back to 0 when off. Any ideas? Thanks

When the ignition is switched on, power is applied to the various gauges and other items on the cluster through the pink wire at the cluster plug. From the plug, power is distributed via traces on the printed circuit board. The gauges and their needles have no "assigned" position when the ignition switch is turned off. Power is removed from the gauge circuit and gravity takes over.

Referencing the last sentence in post #6.. With the ignition ON, disconnect the wire at the temp sensor. The gauge needle should move all the way to cold.. Ground that wire and it should move to the full hot position. If the needle only moves part way each direction, you probably have a bad gauge or at least a bad resistor on the gauge.. If the needle doesn't move at all, time to dig out the wiring diagram and trace out all the wires in the gauge circuit.. Being color blind, you're at a serious disadvantage...

 

[brooksman9]

I did finally find it on the wiring diagrams. On a separate page than the one I was looking at. Looks like it does indeed feed from the circuit board as stated. The needle does not move at all in any direction. I thought it had at one point but I guess I could be wrong. Being color blind does not help but being an electrician does. lol. Just not an automotive electrician. It's mostly the same though. Just have to find the right page. I'll probably pull the dash bezel and see what's going on. Curious as to what those other two wires were that I saw now too. Don't like not knowing the running temp although it has not given me any issues as of yet. I'll take my digital temp gauge home to check as well. Thanks.