Temp Gauge, Dome Lamp & Turn signal indicators do not work

[4thGenC10]

I just replaced all of the gauges, bulbs/sockets and printed circuit on my 72 C10 and everything works with the exception of the temp gauge, dome lamp and turn signal indicators. It seems odd that the 3 problems don't seem to be related but must be somehow. All worked prior to replacing everything. Any help would be greatly appreciated!

[pjmoreland]

There is a black ground wire that comes from the main connector to your gauge cluster. The black wire has a clip on the other end that should be attached to the metal of your dash. Is it still connected to the dash? There are also a couple of screws that pass through the circuit board and should have curved little spring washers under them. Are those installed?

[4thGenC10]

PJ - The black wire (ground )with the clip at the bottom of the dash is firmly connected. I just took a look at the picture I took of the original printed circuit before I removed anything and I can't locate the screws that would have the curved springs under them.

[4thGenC10]

I fixed the dome lamp issue now it's down to the turn signal and high-beam indicators and the temp gauge.(pegged on hot)

[pjmoreland]

This thread is about a temp gauge that was pegged hot. Turned out to be a bad resistor. Since the resistor is connected to ground through the case of the gauge cluster, you might get the same behavior if you have a bad ground.

https://67-72chevytrucks.com/vboard/...d.php?t=812955

[pjmoreland]

Here are the two ground screws

[4thGenC10]

This is great info. I did replace the ground screws for sure but don't ever remember seeing any "springs" or washers. I also installed the original resistor and when the gauge didn't work I read in the catalog that the new gauge did not require one so I removed it thinking that was the problem but it didn't change anything.

[pjmoreland]

I see two potential reasons for the needle to be pegged hot:

1) The lack of a good resistor connected to a good ground (maybe internal to the reproduction gauge)

2) A short on the signal circuit coming from the sender on the engine

These two conditions would result in the needle being forcefully positioned at the pegged hot position. It is also possible that the needle is just coincidentally hanging out at the hot position, but would just as easily hang out in any other position it was left in. That would be the result of a faulty resistor connection and no signal from the sender. Do you see the needle move at all when you turn the key from off to on?

[4thGenC10]

The needle does not even twitch when powered on or off. The sending unit and wiring at the engine harness are new and worked before I replaced the gauge. I have not let the engine run for long to see if it eventually moves but I would think it would start in the cold position.

What could explain the turn signal and high beam indicators not working but the dash lamps work?

[pjmoreland]

Originally Posted by 4thGenC10

The needle does not even twitch when powered on or off. The sending unit and wiring at the engine harness are new and worked before I replaced the gauge. I have not let the engine run for long to see if it eventually moves but I would think it would start in the cold position.

What could explain the turn signal and high beam indicators not working but the dash lamps work?

Yeah, that is an odd little detail there. Your dash lamps get their ground through the screw on the left in the photo I posted above, whereas your turn signal and high beam indicators get their ground through the screw on the right. Maybe the screw on the right needs to be cleaned and tightened up a bit.

[pjmoreland]

Did you paint the gauge cluster tins? If you did, then that could have an effect on your ground connections.

[4thGenC10]

No, I didn't paint the tins and the gauges are new. I'll try removing and cleaning both ground screws and see if that does the trick. Still not sure what to do about the gauge but thank you so much for the help!

[pjmoreland]

I'd focus on getting the indicator lamps working first. Maybe the temp gauge issue is related to that issue.

[4thGenC10]

10-4 Thanks again!

[RustyPile]

Check to be sure none of the tabs on the circuit board are bent back and not making contact with the cluster plug terminals... also, make sure they are clean and shiny..

Let's address the turn signal issue.. The front turn signals work independent from the rear ones.. Simply stated -- the turn signal switch has two "sections", one for the rear because the brake lights and rear turn signals share the same filament.. The fronts have their own "section" on the turn signal switch.. The turn signal indicators work in conjunction with the front turn signals.. Now the question is -- Do the front turn signals work as they should?? If so, the first thing I'd check is the indicator bulbs.. If they're good, check to be sure signal voltage is appearing at the cluster plug.. The light blue wire is the front left turn signal.. Dark blue is the right front.. If you have "blinking signals" here, the problem is bad contacts at the cluster plug, bad ground or poor contact between the bulb socket and circuit board, or poor contact between the socket and bulb....