Instrument gauge cluster bulb replacement.. now no left turn lights?

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FireTruck1984

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1984 Sierra- I pulled the gauge cluster to change bulbs to LED (with great results).. but now I have no left turn indicator light on the dash and no working left turn signals. Right side still works as always. And all tail lights/brake lights/parking lights work as well.
Any ideas what could cause this? Thanks for your help in advance... FireTruck
 

just_some_guy

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This sounds even stranger than what mine was doing. I have some messed up stuff going on with my gauge cluster right now, too. It was even worse a while back but I did manage to fix this particular problem easily. I had no turn signals at all, and when I hit my brakes the turn signals in my grille would both light up at the same time as well as both turn signal indicator lights in the gauge cluster. If I tapped my brakes really fast it looked like my hazard lights were on. I went through the fuse box and replaced every fuse - even the ones that weren't blown. Problem was still happening. Turned out the one thing in the fuse box I didn't replace was that big gray 552 plug that controlled the blinkers. Popped that thing out and replaced it with a new one and that fixed the blinker problem. I guess I should have thought about doing that first, but with how strange it was acting I assumed it was some wires crossed or something. Turned out to be an easy fix. Sounds different than what you're experiencing but maybe it wouldn't hurt to try?
 

FireTruck1984

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This sounds even stranger than what mine was doing. I have some messed up stuff going on with my gauge cluster right now, too. It was even worse a while back but I did manage to fix this particular problem easily. I had no turn signals at all, and when I hit my brakes the turn signals in my grille would both light up at the same time as well as both turn signal indicator lights in the gauge cluster. If I tapped my brakes really fast it looked like my hazard lights were on. I went through the fuse box and replaced every fuse - even the ones that weren't blown. Problem was still happening. Turned out the one thing in the fuse box I didn't replace was that big gray 552 plug that controlled the blinkers. Popped that thing out and replaced it with a new one and that fixed the blinker problem. I guess I should have thought about doing that first, but with how strange it was acting I assumed it was some wires crossed or something. Turned out to be an easy fix. Sounds different than what you're experiencing but maybe it wouldn't hurt to try?
I’ll give that a try, thanks
 

75gmck25

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First check would be the instrument panel ground. On your newer truck I believe there is a ground point bolted on up under the dash on the firewall, and your ground wire connects to it. On older trucks it was a black wire connected to a post on the top of the emergency brake mechanism.

When this panel ground is disconnected, your instruments “find” ground through other devices. It always screws up a few panel lights and one turn signal.

The other check would be the big multi-wire plug on the back of the panel. It connects a lot of wires at once, and if it’s misaligned or the circuit board sheet is pushed to one side, you might get some cross connections.

Bruce
 

FireTruck1984

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First check would be the instrument panel ground. On your newer truck I believe there is a ground point bolted on up under the dash on the firewall, and your ground wire connects to it. On older trucks it was a black wire connected to a post on the top of the emergency brake mechanism.

When this panel ground is disconnected, your instruments “find” ground through other devices. It always screws up a few panel lights and one turn signal.

The other check would be the big multi-wire plug on the back of the panel. It connects a lot of wires at once, and if it’s misaligned or the circuit board sheet is pushed to one side, you might get some cross connections.

Bruce
Thanks for the info Bruce, I’ll check those spots
 

Dmack

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As stated above, led bulbs can be polarity sensitive. Also, I believe some take a special led flasher unit.
 

79Square

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I think yours has the gauge cluster plug that plugs inside the gauge cluster and connects to rows of ribbons. The left signal ribbon may have gotten kinked or folded when plugging it in and is not getting a good connection. Just a suggestion.
 

FireTruck1984

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I think yours has the gauge cluster plug that plugs inside the gauge cluster and connects to rows of ribbons. The left signal ribbon may have gotten kinked or folded when plugging it in and is not getting a good connection. Just a suggestion.
Thanks 79Square, I’m still troubleshooting and will check that connection
 

hunters628

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When I replaced all my stuff with LED in my vw and my Ford I had the same issue. Turned out that the flasher was not happy with the dash lights. Need to get one of those digital flasher relays with the extra ground wire and you’ll be golden.
 

FireTruck1984

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High Sierra K1500 350. Sierra Classic C1500 305.
Engine Size
350, 305
First check would be the instrument panel ground. On your newer truck I believe there is a ground point bolted on up under the dash on the firewall, and your ground wire connects to it. On older trucks it was a black wire connected to a post on the top of the emergency brake mechanism.

When this panel ground is disconnected, your instruments “find” ground through other devices. It always screws up a few panel lights and one turn signal.

The other check would be the big multi-wire plug on the back of the panel. It connects a lot of wires at once, and if it’s misaligned or the circuit board sheet is pushed to one side, you might get some cross connections.

Bruce
Bruce, I checked and addressed the trouble areas you suggested and everything works! Thanks for the help
 

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