Hello all -
long time lurker, first time poster.
I live in North Texas, where heat destroys all things. despite that, I've been able to keep my 2002 Trailblazer LS running (and with ice cold A/C[ironically not one of my issues]) for a good 5 years since I bought it. when I first bought the truck, I drove it home from Oklahoma without an issue. the next few days of driving I started having weird electrical...ignition would cut out randomly while driving, completely shut off, etc. Shortly came to just shut off one day in a parking lot and towed to the magic mechanic. he immediately says ignition switch - I come back with the part and he's got it running and scratching his head. few days of poking around says some under dash wiring was the culprit, bam, ok. good to go.
so minus that Chuck (the truck) has been pretty dependable except for a starter here, hoses there etc. however...just like I've read dozens of times over the net I've been chasing one problem after another ever since. I'm at a point where I'm exhausted of pulling the thread so looking for any useful input. I'm sure I won't catch them all in one go around but I'll give it a shot:
All the lights flicker, all the time. It's less noticable in the headlights and running lights (EG license plate & rear markers) but it's there. Interior dome, dash, manual AC control indicator lights, all of them. frequency does not seem to be affected by engine speed.
- I have checked and cleaned any ground location listed in the service manual. I reinforced the shock tower-engine block-front driver side fender ground with double run 8guage electrical cable. wire brushed and reseated bolts.
fan clutch was replaced by previous owner. seems to engage and disengage more "normally" than not according to the wait 2 mins for device to fully engage or disengage held at 2100 RPM and blah blah blah and it will be engaged if it was turned off while engaged and turn into an Airbus 320 and take off into the night sky. ahem.
-my issue with the fan clutch seems to be more related to the heart of the electrical which I'll get to - however - I don't feel like it should be matching engine speed 100%. at times under acceleration it acts as if it's stuck in the engaged position, matching engine RPM speed up to 4-5k before finally disengaging. I believe it also might be the cause of an incredibly rough idle at times when the AC compressor is engaged while parked.
Chuck also eats alternators. I got the lifetime warranty alternator from O'reilleys auto parts and about every 2 years I replace it. this last time the coils had gone almost black inside. previous one failed to regulate voltage, swinging pretty much randomly between 13-14.8 all the time. it doesn't seem to reliably charge or output voltage over 13.5-13.6 with a brand new alternator and brand new Duralast battery. I have an external voltage monitor wired in, in conjunction with OBD monitoring and just watching the in dash voltage gauge. when turning the headlights on there are times when it will swing up in the 14's for a bit and then dip down to 13.5. I know what you're going to say - yes this can be a normal operating condition, but the standing battery voltage with ignition off at this time is 12.3v. with a brand new battery and alternator less than 2 months old it should be charging strong.
in addition to rough idling, I get near-stalls, dimming headlights, reduced performance at times...and it all seems to be intermittent and unable to reproduce. sometimes I'll get in the truck and it runs like a top. other times I have crazy short term fuel trims and timing advance at idle (can post video and log ScanXL Pro dashboard/logs later), dash lights dim to the point of almost cutting out, poor AC blower performance.
Ive replaced the MAP sensor, checked continuity of fan relay circuit, cleaned the throttle body, checked EVAP purge valve, traced vacuum lines connectors, fuses, pulled up carpet, pulled off panels, jacked it up, taken off tires over the years and I'm pretty much lost since I've had little to no luck. I do have an aftermarket amp and single 12" sub in the back which I've fully disconnected, completely removed from the vehicle, rewired, regrounded, replaced the whole system and it made zero diffference.
being partial disabled makes it hard to get out in the friggin heat to wrench on this thing during the summer but if I dont want a car payment I feel like I gotta solve this issue sooner than later. any takers?
long time lurker, first time poster.
I live in North Texas, where heat destroys all things. despite that, I've been able to keep my 2002 Trailblazer LS running (and with ice cold A/C[ironically not one of my issues]) for a good 5 years since I bought it. when I first bought the truck, I drove it home from Oklahoma without an issue. the next few days of driving I started having weird electrical...ignition would cut out randomly while driving, completely shut off, etc. Shortly came to just shut off one day in a parking lot and towed to the magic mechanic. he immediately says ignition switch - I come back with the part and he's got it running and scratching his head. few days of poking around says some under dash wiring was the culprit, bam, ok. good to go.
so minus that Chuck (the truck) has been pretty dependable except for a starter here, hoses there etc. however...just like I've read dozens of times over the net I've been chasing one problem after another ever since. I'm at a point where I'm exhausted of pulling the thread so looking for any useful input. I'm sure I won't catch them all in one go around but I'll give it a shot:
All the lights flicker, all the time. It's less noticable in the headlights and running lights (EG license plate & rear markers) but it's there. Interior dome, dash, manual AC control indicator lights, all of them. frequency does not seem to be affected by engine speed.
- I have checked and cleaned any ground location listed in the service manual. I reinforced the shock tower-engine block-front driver side fender ground with double run 8guage electrical cable. wire brushed and reseated bolts.
fan clutch was replaced by previous owner. seems to engage and disengage more "normally" than not according to the wait 2 mins for device to fully engage or disengage held at 2100 RPM and blah blah blah and it will be engaged if it was turned off while engaged and turn into an Airbus 320 and take off into the night sky. ahem.
-my issue with the fan clutch seems to be more related to the heart of the electrical which I'll get to - however - I don't feel like it should be matching engine speed 100%. at times under acceleration it acts as if it's stuck in the engaged position, matching engine RPM speed up to 4-5k before finally disengaging. I believe it also might be the cause of an incredibly rough idle at times when the AC compressor is engaged while parked.
Chuck also eats alternators. I got the lifetime warranty alternator from O'reilleys auto parts and about every 2 years I replace it. this last time the coils had gone almost black inside. previous one failed to regulate voltage, swinging pretty much randomly between 13-14.8 all the time. it doesn't seem to reliably charge or output voltage over 13.5-13.6 with a brand new alternator and brand new Duralast battery. I have an external voltage monitor wired in, in conjunction with OBD monitoring and just watching the in dash voltage gauge. when turning the headlights on there are times when it will swing up in the 14's for a bit and then dip down to 13.5. I know what you're going to say - yes this can be a normal operating condition, but the standing battery voltage with ignition off at this time is 12.3v. with a brand new battery and alternator less than 2 months old it should be charging strong.
in addition to rough idling, I get near-stalls, dimming headlights, reduced performance at times...and it all seems to be intermittent and unable to reproduce. sometimes I'll get in the truck and it runs like a top. other times I have crazy short term fuel trims and timing advance at idle (can post video and log ScanXL Pro dashboard/logs later), dash lights dim to the point of almost cutting out, poor AC blower performance.
Ive replaced the MAP sensor, checked continuity of fan relay circuit, cleaned the throttle body, checked EVAP purge valve, traced vacuum lines connectors, fuses, pulled up carpet, pulled off panels, jacked it up, taken off tires over the years and I'm pretty much lost since I've had little to no luck. I do have an aftermarket amp and single 12" sub in the back which I've fully disconnected, completely removed from the vehicle, rewired, regrounded, replaced the whole system and it made zero diffference.
being partial disabled makes it hard to get out in the friggin heat to wrench on this thing during the summer but if I dont want a car payment I feel like I gotta solve this issue sooner than later. any takers?