Turning on the lights turns on the fuel pump

[Warriorpluto]

I have a strange issue with my 07 Denali. When I turn in the headlights manually the fuel Pump primes and the check engine light comes on the dash like I'm turning the key on. If the lights are on when the truck is running and I try to turn it off, the truck will continue to run with the key out. Once I turn off the lights the engine will power off. It's this the ignition switch failing?

 

[Doubeleive]

I have a strange issue with my 07 Denali. When I turn in the headlights manually the fuel Pump primes and the check engine light comes on the dash like I'm turning the key on. If the lights are on when the truck is running and I try to turn it off, the truck will continue to run with the key out. Once I turn off the lights the engine will power off. It's this the ignition switch failing?

that's a new one, lol
I would try a new light switch first they should be like $25

 

[petethepug]

Did the previous owner brag about his stereo installation skills or has the truck had a change over to a bunch of LED bulbs?

 

[wjburken]

Is this a new “feature” or has it been like this for a awhile?

 

[intheburbs]

Does it have an aftermarket alarm system?
Does it have an aftermarket audio system with extra amps?
Any other signs of aftermarket wiring?

I'd guess somebody didn't do some kind of install properly.

Only other possibility is that the PO had it wired specifically to do that. How many miles and engine hours on it?

 

[BlaineBug]

Does it have an aftermarket alarm system?
Does it have an aftermarket audio system with extra amps?
Any other signs of aftermarket wiring?

I'd guess somebody didn't do some kind of install properly.

Only other possibility is that the PO had it wired specifically to do that. How many miles and engine hours on it?

Aftermarket alarms, remote starters, and keyless entry systems - they're guaranteed to have a crappy wiring job to begin with, but even if they didn't, the circuit board often fails. And they control everything he mentioned - lights, ignition, etcetera. Sounds like some circuits got shorted. The best "fix" is to rip all of that aftermarket stuff out and repair all of the pierced/cut wires!

 

[Warriorpluto]

Sorry guys. I found out what it was. I had left for overseas and did an Escalade cluster swap. I didn't notice the problem before I left. I was thinking it was the ignition switch. I had the yellow wire going to the pink wire. On an Yukon and Tahoe this wire is supposed to be discarded. No issues since I disconnected it.

 

[BlaineBug]

Sorry guys. I found out what it was. I had left for overseas and did an Escalade cluster swap. I didn't notice the problem before I left. I was thinking it was the ignition switch. I had the yellow wire going to the pink wire. On an Yukon and Tahoe this wire is supposed to be discarded. No issues since I disconnected it.

Glad to hear that it was an easy fix.