2003 Chevy Trailblazer 2003 Trailblazer stalls when A/C on

POSSUMBELLY

MEMBER
2003 CHEVROLET TRAILBLAZER
6 CYL
2WD
AUTOMATIC
88,900 MILES

My 203 trailblazer after replacing the battery was shutting off when I turn the a/c on while at a red light, the idle rpms were around 400 and bamm. Off it went.

My fix. First ---->DISCONNECT THE BATTERY<

Second ----> took off the electronic throttle body, cleaned it, I used the entire can of cleaner, dont be stingy, use the entire can. Use a brush and clean rags, and paper towels, get it as clean as new, mine was brown it had so much gunk, clean the bolts, clean the plastic air intakes, clean everything.

Third ----> put it all back together.

when I got it all back together, I reconnected the battery, opened the fuse cover, fuse number 31 is the throttle body fuse, atleast on mine.
Took it out for 5 minutes, put it back in, closed the covers, left the hood open, turned the truck back on, it purred. It was sooo nice, after 5 min, I turned the highbeam lights on, the rpms at 500rpm did not even move, tuned the fan on at max, my trailblazer has the rear a/c fan turn it on as well, turned the radio on and all the inside lights on, and the emergency flashers, and left it idleling for 20 minutes,

after I went in and cleaned up, I drove it on the interstate for 70 miles round trip at 80mph, yes I was told 50 is enough but I'm a rebel without a clue, so I went an extra 20 miles, when I got off the interstate my rpms were down to ZERO. Dont freak out, I almost did, but the truck did not shut off even with the a/c on, I got right back on the interstate and drove it back towards home, got off at a rest area and let it idle with lights, a/c, and radio on, the rpm showed zero, but the idle was fine, turned the truck off for 5 min, turn it back on, and the rpms were back to normal, idle is normal, no issues what so ever. Drove back home, got into some stop and go traffic, and no problems at all. It idles like new.

so before you spend $200 or more at a repair shop give this a try, a retired GM mechanic told me to do what I did and what it turns out to be is that the computer on the trailblazer has to relearn, once you unplugg that battery, the computers memory wipes it self out, and it needs to re learn. So good luck and I hope this helps you out, like I said my 2003 TBLZR is now running like a champion. After giving me soo many problems after replacing the battery.

3 Replies

NEVERBUYACHEVY

MEMBER
9 POSTS

I've been fighting the same problem for the last year plus. In time you will likely get a trouble code setting off the check engine/service engine soon light. The trouble code will be for the cam shaft position sensor and the crankshaft position sensor. I was Unfortunate enough to bring it to the wrong dealer for the first 3 tries to fix the problem and got ripped off. With research on line and talking with several mechanics I was told and found out one sensor will set off the other and both will need to be replaced. They are not too expensive, 80 U.S. Dollars for the two parts. After the sensors are changed the PCM will need to "relearn" the timing of the engine. This almost has to be done at a GM dealer, and cost about 80 U.S. Dollars. Total time to replace both sensors should be 1/2 hour. The cam shaft sensor is very easy to change, the crank shaft sensor is a bear to get at. I choose to change the cam sensor myself, but couldn't reach the crank sensor. Change both sensors and have GOOD DEALER relearn the computer system. Mine seems to be working for now, best of luck.