2004 Tahoe Z71. I've looked through the AC runs hot threads, but my issue seems a bit different. Every few months I'll start driving and the AC blows hot. It blows hot on both sides. It does not change while I'm driving, it's just this way from the get go once in a while. I can fix this by simply turning the car off and back on. This workaround has never failed me. Is this still a bend door actuator issue?
AC sometimes blows hot, but re-starting fixes it
- Thread starter siberian
- Start date
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swathdiver
Full Access Member
Probably but why keep guessing? Get a bi-directional scan tool on it and pull the BCM codes.
Depending on the HVAC control module, it could need an updated calibration, or simply a reset. And @swathdiver's recommendation to get an advanced scan tool on it so you can see what's going on is solid. Maybe someone around you has a Tech 2, but we don't know where you're located.
from my experience with the same issue, it could be 1 or all 3
1. low freon r12, r123 -whatever it has
2. possible stuck actuator
3. glitchy hvac control (the digital ones can go bad and will do this behavior)
trouble shooting it is difficult especially when it is intermittent
on my 03 I had both low freon and a glitchy hvac control
had it evacuated and refilled-worked better but was still occasionally blowing hot air
replaced hvac control- solved problem completely
previous to the refill and control head replacement it would either just blow hot air, or it would start out cool and after a bit just blow hot air, turning it off/on sometimes worked, turning the vehicle off/on also sometimes worked, sometimes it worked fine the whole trip and sometimes it would work and then while sitting at red light would start to blow hot air and it would have to be power cycled again as above.
1. low freon r12, r123 -whatever it has
2. possible stuck actuator
3. glitchy hvac control (the digital ones can go bad and will do this behavior)
trouble shooting it is difficult especially when it is intermittent
on my 03 I had both low freon and a glitchy hvac control
had it evacuated and refilled-worked better but was still occasionally blowing hot air
replaced hvac control- solved problem completely
previous to the refill and control head replacement it would either just blow hot air, or it would start out cool and after a bit just blow hot air, turning it off/on sometimes worked, turning the vehicle off/on also sometimes worked, sometimes it worked fine the whole trip and sometimes it would work and then while sitting at red light would start to blow hot air and it would have to be power cycled again as above.
Mudsport96
Full Access Member
My Silverado does this once in a while. My issue is either the coil that pulls the clutch in on the compressor is weak, or the air gap is too great for it to magnetize and be pulled. Only happens when it cycles, once it is engaged it stays engaged. So if i run it on max it is fine but on regular sometimes it wont re-engage. Probably can fix it by reshimming the clutch.
So yeah next rime it blows hot, pop the hood and see if the compressor is engaged.
So yeah next rime it blows hot, pop the hood and see if the compressor is engaged.
BossGunner
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I actually just ran into this with 04 hoe. First easiet thing I was able to do was pull the hvac 10amp fuse (under the hood just above the rear window wiper 25 Amp fuse) wait 5 mins, put it back in, turn the truck on for 3-5 mins, turn off for 30 seconds, turn back on and it reset the passenger side actuator. There's a decent video on how to do this. Worked for me but not sure if you've already tried this.
I was gonna recommend a reset but by unhooking the battery cables but I like this better and hope it works for you.
PatDTN
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I had a bunch of odd things with the HVAC on my '09 and eventually replaced the battery. I had replaced the battery with one from Wal-Mart years ago and it seems to have failed oddly. New battery is AGM and fixed things. Just a thought for y'all with even older vehicles. Oh and check for corrosion on both ends of battery cables and engine ground strap.
GreenTahoeZ71
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As another mentioned, get a good scan tool.
I would also check your alternator to make sure it's putting out within specs.
I just chased numerous problems being caused by a bad voltage regulator In a brand new alternator from auto zone. It was overcharging my system which fried my throttle body sensor numerous times and my PCM and my hvac module.
I bought a Remy alternator and it finally passed an alternator test on my scanner.
