2002 Trailblazer Electrical Problem Shuts OFF

Hi,
This may get a little lengthy. In Jan my gas pedal stopped working when I turned on headlights. TPS unit on motor burnt because of headlight circuit used it as a ground. Replaced TPS and run new gounds for light circuits as could not find problem. Drove it a few weeks and then it just shut off going down highway. Towed in and no fuel pressure, they replaced fuel pump and sending unit. Very expensive. Drove a couple of weeks and it shut off again going down highway at 65mph. Towed in and replaced Ignition switch module. Run a few days quit again. Towed in. It started ok and run ok could not find problem. Drove it one day, shut ogg again. Towed in. Up until now no codes shown at all when tested. Now it showed Anti Theft Pass Key system programing corrupt. Flashed it and downloaded new program from GM computer at dealer. Run 2 days fine and then it would not start in my driveway. Took out fuel pump relay and put same one back in and it started fine. Turned on AC and it shut off. Exchanged fuel pump an AC relays started fine and run fine with AC on.. Leads them to believe there may be a problem in fuse box/relay box itself. Now I am afraid to drive it and have run out of money and Patience to. Can anybody on this forum suggest anything to check or try? Anyhelp would be greatley appreciated. There have been 4 techs working together on this. 2 from very good independent and 2 from GM dealership.
Thank You
TrailblazerBob

fuse box problems would make sense, especially if some problems are fixed after switching relays/fuses

bad grounds, faulty computer, burned out IC's,

my first guess is loose ground wire somewhere... shorting randomly, anything not working which used to?

almost sounds like too many things to check to be worth it...

Hi,
I want to thank everyone for their postings to my original question. I think they have finally found the problem. Under the hood on the left fenderwell is mounted the fuse and relay box. The bolts that hold the top part of box (with the fuses and relays ) to the bottom part of box ( where the wiring harness connect) had all worked loose, I mean really loose. Tightened all of them and so far have not had any problems. They put about 250 miles on it and then called me to come get it. They had no problems and so far neither have I. I guess it was loose enough that it was losing contact between harness and fuses and relays. Have no idea how it got so loose. Hope this might help someone else.
Trailblazerbob

Good info, very unusual issue also, thanks for the post back.

2002 trailblazer 91000 miles. All elecrical also went out. Took the car to my mechanic and he told me to put a new battery in and take it to the dealer for a recall on the cluster panel. Dealer said they already did the recall but the ignition is the problem. Now they did that for $350 and said the ignition is good but the gauges are still acting erratic. They told me they need to start stripping the panels inside of the vehicle to look for a short in the wiring. I asked them how much it would cost they replied " It could take an hour or 2 days? we won't know until we find the short!" I told them do you just want an empty check to fill out when you find the problem. Now im stuck 350 dollars short and still a bad car. No More GM.

try starting a new topic, you will get more hits

I am looking at getting a 2002 Envoy XL/Trailblazer for winter time use.
Is there a problem with the turn signal switches like there was in my 04 Monte?
Notice on the test drive the left turn signal blinked fast like it had a burned blinker bulb and 2 days later now wondering if it might be a turn signal switch. I didn't look at bulbs or see if the turn signals where blinking on the test drive.
What other problems to watch for on the 2002?

2002 was a tough year for these trucks, many recalls, many tech bulletins poor reliability in general, including mine. I would try and get at least a 2004. BTW satret a new thrad when the topic is not related, thanks.