Envoy Headlight Controls

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csherman
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Joined: Mon Jun 17, 2013 1:05 am

Envoy Headlight Controls

Unread post by csherman » Mon Jun 17, 2013 2:50 pm

Our '06 Envoy head lights have a mind of their own much of the time they stay on for an excessive amount of time killing the battery. Some times they go off immediately, I've even seen them come on while parked. There is no adjustment for how long they stay on so what controls them?


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carriedi
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Joined: Wed Apr 10, 2013 12:42 pm
Location: Oregon

Re: Envoy Headlight Controls

Unread post by carriedi » Tue Jun 18, 2013 7:08 am

the headlights are controlled by the body control module under the left rear seat on rear fuse block. Try scanning the BCM and see if there are any codes. Is it just the headlights that come on or does the running lights come on too. the lowbeam relay is #46, the highbeam is #43 (under hood fuse block) and the running lights relay is #30 (in rear fuse under rear seat)
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LuvGMC
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Joined: Thu Nov 17, 2016 4:57 pm

Re: Envoy Headlight Controls

Unread post by LuvGMC » Thu Nov 17, 2016 5:12 pm

I have a GMC Sierra..checked all the relays and grounds. The truck will not shut off until the one of the head light fuse is taken out. When headlights is switched to off the fuel pump shuts off too. Why would the headlights have control of the relays?

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carriedi
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Joined: Wed Apr 10, 2013 12:42 pm
Location: Oregon

Re: Envoy Headlight Controls

Unread post by carriedi » Sat Nov 19, 2016 7:33 pm

GMC Sierra wiring diagrams change over the years. What is the year, model, engine, trans and drive train (2 or 4wd) do you have?

Also you say when you one headlight fuse, which one? or does that make any difference? Either one can shut off the fuel pump?

Here's the thing, it's gotta be more than just the fuel pump that keeps running. Or are you saying the fuel pump keeps running but the truck shuts off? If the engine keeps running then it's a lot more than the fuel pump keeps running. That would mean the the computer is not seeing the ignition switch power off. That why the spark and fuel injector keep working as well as the fuel pump. If the computer doesn't see the key turn off I would look for a short to power somewhere in the computers battery feed wire and the power to the headlight power circuit.
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