2 Problems ...Fog Lights and Door Locks

I have 2 issues that I am hoping you guys can help me with. I have an '01 Silverado 1500 Z71 LT with 70k and some electrical issues.

The first, and most annoying, are my electric door locks. They were working fine six months ago when I got the truck, but now they will:
1. not lock or unlock with the door switch at all
2. lock only randomly with the remote, usually after driving long distances
3. always unlock with the remote(thank goodness)
4. allways lock when I hit 15 mph and unlock when the key is pulled out
I have changed the remote battery, reprogrammed it and checked all the fuses. Could it be a relay? What else is there? How do you test a relay?

The next issue is the fog lights. They don't work at all. been like that since I bought it. I have checked fuses and put in 2 different sets of bulbs. Could this also be the relay?

Thank you up front for any and all responses to these issues. The locks are driving me crazy.:banghead: Always having to listen to see if it locked or if I need to get back in and crawl accross to lock the other door.

The fog lights don't come on when the E brake pedal is anything other than fully released. Even the slightest nudge can be enough to make the truck think the E braks is engaged.
Try pushing the ebrake all the way in and pull the release to let it go all the way up.

If it's not this I'm thinking the E brake sensor (someone else can say what/where it is) might be the offender.

Good Luck!

I use my ebrake all the time, so i don't think that is the problem. If the sensor is bad, wouldn't that cause problems with my headlights as well?

You're making sure you're headlights are on with the fogs as well? The foglights, at least experience with my dad's '01 Tahoe, they do not come on except with the headlights. Stupid design if you ask me.

I use my ebrake all the time, so i don't think that is the problem. If the sensor is bad, wouldn't that cause problems with my headlights as well?

I believe it would. Dumb question - have you checked the bulbs?

Headlights on or off..doesn't matter. I have tried a few sets of bulbs.

I have 2 issues that I am hoping you guys can help me with. I have an '01 Silverado 1500 Z71 LT with 70k and some electrical issues.

*snip*

The next issue is the fog lights. They don't work at all. been like that since I bought it. I have checked fuses and put in 2 different sets of bulbs. Could this also be the relay?


I cannot help on the locks, but I have worked on the fog light issue. I have a 2000 Z71 LT. Factory fog lights quit at about 60,000. I happen to have the factory service manuals and started through the diagnosis steps in the manuals. I checked every bulb, wire, relay (in the underhood fuse pane), switch (in the dash), etc. Turned out there was one thing left - the on board computer that handles the interior components which is mounted under the driver's dash. Turns out that part of the circuit for the lights runs through the computer - this is how Chevy engineers handled the process of turning the fog lights off which high beam is switch. Ended up costing about $400 to have the computer replaced and reprogrammed at the dealer. I could have purchased the computer and installed it but it was still going to the dealer in order to have it reprogrammed for my VIN and option codes (I was told). Dealer would stand behind the work if they installed the computer but not if I did.

All I can say is my class A personality is calm now and the lights work. I should have gone ahead and done like my wife suggested and purchased bright, useable aftermarket lights and installed them. It would have been a lot cheaper. However, something was telling me that if that circuit in the computer had failed what else might....

That brings up an interesting possibility. I know that if you add the fog lights afterward, the computer needs to be "told" that they are there for the switch to work. Is it possible that the previous owner added the lights himself (you can pick the OEM lights up on ebay for fairly cheap, and the switch) but didn't get the computer updated? Probably not likely, just a thought...

It is possible that the prior owner did just that but I do not think it to be probable. I would estimate the prior owner would have either had the programming done and/or purchased a wiring relay and direct wired them.

I do know that working through the schematics, there is a lot of stuff on that truck that run through this particular computer - if I recall correctly, it may also involve your door locks (but do not hold me to that one).

Thanks for the input. I still have headlights(for now), the locks are a bigger issue than the fog lights, but if they go to the same computer ...crap. Someone else with a similar problem told me that he unhooked his battery for a few minutes and that reset his computer and fixed his locks. I'll try that and then I guess I will tear the door apart this weekend and see if there is something wrong in there. I hope its not the computer, I really don't want to spend a bunch of cash on that ... I would much rather get a cat-back with it.