Gauges and headlights electrical issue

[thecantaloupeman]

So I'm combining all of my other threads into one because now I'm convinced all of this is somehow connected.

It all started with my fuel gauge issue. The gauge reads past full and slowly goes towards empty until you turn the key, then it pegs all the way to 3 o clock. I was told to check my sending unit ground, but never was able to find it.

Just recently I disassembled the gauge cluster to make the lights brighter by replacing the bulbs. Then I was told to check my headlight switch resistor. That seemed corroded so I replaced it. After I did this I started having super weird electrical issues with the switch.

I put the old switch back in, and it didn't fix my issue. Now I think I broke something somehow by disconnecting the headlight switch. Hopefully it's not because the lights were on when I disconnected the switch.

But now when I turn the headlights on and the knob is turned at all left, it makes my blinkers solid green and the fuel gauge starts going towards empty and then reads empty until I turn them off. If I turn the knob all the way right it turns on the dome light and ashtray light.

Could any of this be related? Did I make a mistake by disconnecting the headlight switch while it was on? I was supposed to pull out the knob and press the button to release it. Meaning when I disconnected the switch from the harness it was still on.

I would really appreciate the help. Thanks.

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[78C10BigTen]

That sure sounds like a ground problem or a circuit searching for power elsewhere.

 

[thecantaloupeman]

That sure sounds like a ground problem or a circuit searching for power elsewhere.

Could I have shorted something when I dsconnected the headlight switch like that? I still had the fuel gauge problem, but not the weird solid turn signals and the fuel gauge didn't go down when I turned on the headlights. This became and issue after I replaced the switch.

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[78C10BigTen]

I dont think so.... usually the solid green turns mean something like a bad bulb or shorted tail light kinda thing... as ive found. Someone will correct me if im wrong. I do known the headlight switch causes all kindsa goofy issues.

 

[thecantaloupeman]

I dont think so.... usually the solid green turns mean something like a bad bulb or shorted tail light kinda thing... as ive found. Someone will correct me if im wrong. I do known the headlight switch causes all kindsa goofy issues.

Weird. Yeah I didn't have this issue until I changed out the switch. Hopefully I'll be able to figure this one out. Seems like it's gonna be really complicated. Another thing I should mention, is a missing piece on my cluster. I'll attach the picture, but this would've been missing before I replaced the switch and even took out the cluster.

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[78C10BigTen]

Weird. Yeah I didn't have this issue until I changed out the switch. Hopefully I'll be able to figure this one out. Seems like it's gonna be really complicated. Another thing I should mention, is a missing piece on my cluster. I'll attach the picture, but this would've been missing before I replaced the switch and even took out the cluster.

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My 78 has one like that too. Idr where but i never paid no mind as everything works so

 

[gotyourgoat]

Both green turn indicators light up solid?
Have you verified all bulbs and fuses are working and are the correct size?

 

[thecantaloupeman]

Both green turn indicators light up solid?
Have you verified all bulbs and fuses are working and are the correct size?

I haven't verified all my fuses are working but I replaced the gauge cluster fuse. All bulbs are a 168. The only one I replaced that wasn't originally a 168 was the 194 bulb in the washer switch.

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[gotyourgoat]

Was actually referring to all the light bulbs in the truck.

Do your hazards work correctly? How about other lights, are they working?

 

[thecantaloupeman]

Was actually referring to all the light bulbs in the truck.

Do your hazards work correctly? How about other lights, are they working?

So I took apart the gauges again, and noticed the printed circuit board had a bent tan, so the harmonica clip wasn't engaging with that tab.

I fixed the problem, however my blinkers still blink slightly slower when the headlights are on. Is that normal? The cabin lights also dim slightly. Other than that I think everything works properly.

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[chengny]

So I took apart the gauges again, and noticed the printed circuit board had a bent tan, so the harmonica clip wasn't engaging with that tab.

I fixed the problem, however my blinkers still blink slightly slower when the headlights are on. Is that normal? The cabin lights also dim slightly. Other than that I think everything works properly.

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The headlights are on a branch of share a power supply that also feeds nearly every other circuit in the truck. Mostly through the ignition switch.

If turning on the H/L's causes reduced performance in other circuits, that would suggest a voltage drop in the entire electrical system. Does the volt meter deflect downwards when the H/L switch is pulled out? If so the voltage drop may be caused by a weak battery or alternator.

 

[thecantaloupeman]

The headlights are on a branch of share a power supply that also feeds nearly every other circuit in the truck. Mostly through the ignition switch.

If turning on the H/L's causes reduced performance in other circuits, that would suggest a voltage drop in the entire electrical system. Does the volt meter deflect downwards when the H/L switch is pulled out? If so the voltage drop may be caused by a weak battery or alternator.

I might test out the alternator later. Just replaced my battery. I doubt it is bad, but better safe than sorry. I tested the gauges last night after fixing that bent pin issue, and they are much much brighter after replacing the switch. Absolutely perfect.

Before I put together my dash again though, what is a good way to dust off the gauges without smudging paint? I used a baby wipe on a small area and it smudged white paint and made the 35 on the speedo look a bit cracked. How can I avoid this and still get all the dust out and make the gauges nice and clean?

 

[chengny]

Before I put together my dash again though, what is a good way to dust off the gauges without smudging paint? I used a baby wipe on a small area and it smudged white paint and made the 35 on the speedo look a bit cracked. How can I avoid this and still get all the dust out and make the gauges nice and clean?

Don't touch the painted on details with anything. They will smear very easily. Seems like the white paint smears the easiest.

Remove the gauges and rinse them under a strong stream of warm water in the kitchen sink. That will remove most of the dust. If you still have some dusty areas, use a Q-tip and carefully clean the remaining dust.

 

[Raybo135]

I had this problem, sort of, when the headlights were on, my Right Signal was dim. Turned out it was a small short in the front right marker light. Change out the sockets and it should correct the turn signal indicators from lighting up when the head lights are on.