Dash blinker lights glow when the marker lights are on.

[Broken85]

So, let me start off by saying I did this to my self by installing a Vintage USA dash in my 1985 K10 Silverado shortbed during a full restoration. Mistake, nothing but problems. This is NOT a plug and play upgrade. Expect to spend countless hours with whatever wiring diagram you can find on line, a test light, wire cutters a soldering iron and everything else you would need to destroy a perfectly good dash wiring set up. I am on the 4th tachometer (sending this one back Monday) and I think I am going to put wing nuts on the dash pad to save me time for next time.

Problem: when the marker or headlights are on, I am getting a significant glow from the blinker indicators on the dash. I have tapped the dark blue and light blue for left and right, but I am getting a power bleed somewhere. I can’t find a wiring diagram that is complete enough to track the entire blinker system, but the only place I can see the parking system crossing with the blinkers is at the bulb (yes I have LED aftermarket 1157s). I don’t think anything is pulling a ground. I feel like there is a relay or something that is not grounded now that I have pulled the original that I don’t know about.

 

[Jgonick]

Side marker lights are fed by different directions depending whether your parking lights are on or not. It actually goes to ground through one of the filaments (in dual filament bulb) located in the front park/dir light.

LEDs can be problematic- they only allow current in one direction- unless modified somehow. They also use less current that can also cause problems in some situations -

 

[Broken85]

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[Broken85]

I think you are onto it jgonick. In looking at some tech specs on LED bulbs, they do not operate with two separate circuits (a dim and a bright). They operate with on one circuit with two power modes (low and high) using the same LEDs so the markers are likely crossing with the blinker lights at the circuit board in the bulb causing the power bleed over. I need to find a replacement bulb with two separate circuits. It is not easy to find tech sheets on these light bulbs though.

 

[Broken85]

T

 

[dsteelejr]

I fought the LED fight with my ‘80 K25 three and half years ago using LED bulbs from Amazon. Not for style, but just to have better, brighter exterior lighting.

The front turn/park LED lights worked fine, but the side turn / marker lights only blinked with parking lights off. I messed around with different LED bulbs, load equalizing resistors, and electronic LED flasher to replace to stock mechanical flasher. All to no avail. Had that problem with the glowing turn indicators as well.

What it finally came down to was keeping the front LED bulbs since they worked fine, getting a set of amber LED side markers from LMC (these were complete, one-piece, sealed electronic units—lens and lights) and replacing the mechanical flashers with Painless electronic LED flashers. I’ve have had no problems since.