taenumbanine
TYF Newbie
My AC compressor doesn't shut off unless I pull the under hood fuse. Does anyone have any suggestions on what needs a replacement?
Sent from my LGLS775 using Tapatalk
Sent from my LGLS775 using Tapatalk
A/C Always On?
- Thread starter taenumbanine
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
03z71chevy
Full Access Member
Are your rear HVAC controls on at all? I seem to remember that if I have the rear HVAC set to anything the compressor runs. Also if I have my front HVAC set to AUTO it will run the compressor non stop so I almost always have that setting off.
OP
OP
taenumbanine
TYF Newbie
No the hvac isnt set but I could plug the fuse in now and as soon as the pins make contact the compressor will start up.
Sent from my LGLS775 using Tapatalk
Sent from my LGLS775 using Tapatalk
03z71chevy
Full Access Member
So the compressor runs with the front and rear HVAC off?
OP
OP
taenumbanine
TYF Newbie
Yeah and it drained my battery once or twice before I wised up
Sent from my LGLS775 using Tapatalk
Sent from my LGLS775 using Tapatalk
03z71chevy
Full Access Member
That's odd. Hopefully someone on here has an idea.
mizzouguy
Full Access Member
Am i missing something? The compressor wont turn unless the engine is running. And the clutch wont get power to engage the compressor unless a whole bunch of parameters in the ac system have been met (low pressure switch, high pressure switch, etc). I'd have to look at a wiring diagram but if I remember right, the control unit in the dash is what receives signals from all of the sensors and then gives power to the clutch.
OP
OP
taenumbanine
TYF Newbie
So are you saying my control unit is bad?
Sent from my LGLS775 using Tapatalk
Sent from my LGLS775 using Tapatalk
mizzouguy
Full Access Member
Help me fill in some blanks. Truck is not running, key off, and compressor clutch is energized while not spinning? As in it has 12 volts at the clutch connector? Start the truck and the compressor is always engaged no matter what you do with the controls inside and the clutch only disengages when you pull the fuse, effectively cutting the power source?
OP
OP
taenumbanine
TYF Newbie
Yes, key off, the compressor is being fully powered up until I pull the fuse.
Sent from my LGLS775 using Tapatalk
Sent from my LGLS775 using Tapatalk
OP
OP
taenumbanine
TYF Newbie
If you want I could record a video of the compressor starting up as I drop the fuse in with the key off. I haven't fiddled with the control unit since the ac drained my battery the first time
Sent from my LGLS775 using Tapatalk
mizzouguy
Full Access Member
Yeah I've never seen that before. This is on an 00-06 model? A video may help just so I make sure I know what you mean by "starting up" 
OP
OP
taenumbanine
TYF Newbie
Yeah, 03 to be exact. I'll upload the video in a sec.Yeah I've never seen that before. This is on an 00-06 model? A video may help just so I make sure I know what you mean by "starting up"
Sent from my LGLS775 using Tapatalk
OP
OP
taenumbanine
TYF Newbie
Sent from my LGLS775 using Tapatalk
mizzouguy
Full Access Member
Not to seem rude but your video doesnt have sound and doesnt show the ac compressor or clutch at all.
OP
OP
taenumbanine
TYF Newbie
No sound?
Sent from my LGLS775 using Tapatalk
Sent from my LGLS775 using Tapatalk
Z28TWITCH
Member
- Joined
- Sep 18, 2013
- Posts
- 83
- Reaction score
- 27
Not sure what you mean by the compressor is on even when the truck is off...even if it has power to it, its not doing anything, so not sure how it would've drained the battery...secondly, do you have your air set to the windshield at all? if your running the truck with air on the dash at all the compressor will engage because thats how it takes the humidity out of the truck...that would be standard operation. If your hvac controls are set to off and no air to the windshield, then you have got a gremlin. If it were me, Id start with the hvac controls themselves and work from there. If the compressor is turning on and functioning, I wouldn't condemn the compressor itself, clearly something is telling it to work and its just doing what its told. good luck.
retiredsparky
Full Access Member
- Joined
- Jul 9, 2016
- Posts
- 379
- Reaction score
- 121
Tae is saying that the compressor clutch is always powered even when key is off. It definitely should not do that. There is a relay that turns on and off the power to the clutch. The relay is controlled by the dash mounted AC controller.
Until you get this fixed, install a toggle switch hanging on the wiring under the dash that interrupts power to that fuse. Remove the fuse, notice how it has male connectors on it? You can make a connector that fits into the fuse holder slots from crimp wire connectors. Install a remote fuse holder inline with wiring going to the toggle switch. Now you can use the switch to operate the compressor until you fix the problem.
Larry
Until you get this fixed, install a toggle switch hanging on the wiring under the dash that interrupts power to that fuse. Remove the fuse, notice how it has male connectors on it? You can make a connector that fits into the fuse holder slots from crimp wire connectors. Install a remote fuse holder inline with wiring going to the toggle switch. Now you can use the switch to operate the compressor until you fix the problem.
Larry
