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· Premium Member
110 Posts
Discussion Starter · #1 ·
Having some electrical issues with my truck. Currently the Low beams are always on. I parked the truck at noon and then the wife said a few hours ago the lights were on. that means they turned on by themself.

I pulled the relay which obviously turned them off, and I put a different one in that worked and they immediately went on. I pulled the light controller and disconnected it and they stayed on. Disconnected the BCM and they stayed on. With BCM disconnected and turning the key to the run position they turned off, but turned on again when I turned the key off.

Truck has been having IP issues for over a year where it just goes haywire and keeps clicking. Before that the power locks would randomly fire while driving. That is more rare now. But now the IP gauges and lights will work, but the DIC and gear indicator will be blank.

I recently replaced the radio and had to replace the aftermarket interface thing because the old one I accidentally shorted and fried it on the bench. This new one will power off and not come back on until the key is cycled, therefore keeps the radio off.

I did take the ground off under the driver door and grind the frame down to bare metal and clean the ground up. I didn't do any of the others. Looking at the diagram on b-15 from It looks like I only have one ground location and that ground zone 21 and 18 are the same spot, unless ground zone 18 is in the cab, then in that case I only did 21.

I don't have the wheel well covers in and I did drive through a storm yesterday in Iowa, but the lights were fine last night. It also seems to drain my battery before this issue tonight. I thought my alternator was bad and replaced it with the 145amp one.

This morning the truck was a little low on the battery, but still started.
Here's a youtube video of me demonstrating some of this.

· Registered
7,428 Posts
You have the wiring diagram. Look to see where the headlights are grounded, probably under the radiator core support. Also check to be sure your firewall to engine ground is still functioning and carrying a load. See what's clicking under the dash and see what it takes to get that to stop. Likely a clue to your problem.
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