a/c doesn't work?

some of these trucks had a wiring issue leading from switch to resistor. check for weak and very flexible wiring like it's been burnt up. if so there is a kit available from gm dealers or www.gmparts direct.com it's about $100 and you also need to replace the resistor. the purple wire goes to the blower and should have 12 volts. check the fuse and or blower relay under hood. see if power goes to the resistor on lower speeds it may be just a bad resistor as that controls the lower speeds other than high.

This video and guides will help you fix the problem.

https://youtu.be/uZrQCGwXfek

and

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak

and

https://www.2carpros.com/articles/replace-blend-door-motor

Check out the diagrams (Below). Please let us know what happens.

sorry isent the stuff for front blower.....check fuse and blower resistor assembly the red wire shold have 12 volts for blower. see pic.

Fuse is good i ghet 12v the red wire is good too have 12 v just the skini purple wire is 0.05 but you say i have to ghet 12v too i put a new blower motor resistor and it doese the same
Where i ken find the blower motor relay underhood?

sorry I should have done a better job on the answer as i'v e not done this for a while so taking me a bit to get in swing of things. it is item 5 on blower housing. see pic

i dont ghet 12V on skiny purple wire i get just 0.05V what i should to check because you say i have to get 12V where the power is lousing?

if you are talking about the rear your wire colors are all wrong . check the fuse for rear blower under hood it will say rr hvac and also check ign 3 fuse in car. then have a pro scan it for you the control may be bad.

Why does ac change from ac to heat in summer and heat to ac winter front could be drivers side passenger side or both never effects rear

It sounds like your blend door could be jammed open or closed. Another common problem is there is a valve that allows hot water to come through the heater core at the firewall. This could be wedged open/closed. Check to make sure it operates properly. You should be able to hear the blend door moving back and forth when you turn the climate control knob to hot/cold.

It doesn't do it all the time just intermittent the only way to reset it is stop vehicle turn off restart it will be ok for for 10 minutes or all day just depends on how lucky I am

Try a system reset. Start engine, turn off climate system. Stop engine. Turn key on, but do not start. Leave for 10 seconds. Turn off and pull key out of ignition. Leave out for 30 seconds. Restart engine, turn on air conditioning. Try that and see what you come up with.

I tried something similar to this last year it did not help

My vehicle has duel climate control, with rear control. my drivers side blows only heat while the rest is cold and can be adjusted. all modes work, floor defrost etc. but on the driver's side whether its on any mode will only blow hot. I need to replace or clean my actuator or re-calibrate my actuators. where is the drives side actuator? is it the one under the drives side above the pedals? and do you have a procedure to re-calibrate my actuators? all this started after replacing my battery.

89018964 Module, HTR & BLO & A/C CONT this is an updated part # for the blower control unit if that has gone out.

Check this unit as the terminals can melt on them sometimes.

first turn key on and pull HVAC fuse inside truck for sixty seconds then reinstall fuse and see if the actuator works it might. that resets the actuators when you do that. see picture for actuator. the dash has to be removed to gain access.

There is nothing wrong with the blower motor

Let me know how the system reset goes.

If the problem occurs intermittently I would venture to say there is a loose connection/short that is happening in the system.

2004 yukon denali a/c blows hot air from the dashboard passenger vents...all other vents...driver side and rear seats are working properly.....problem started after vehicle was jump started for dead battery.... battery cables also needed to be cleaned...

well we can't clean the cables for ya on here, so you will have to have someone else do it or do it your self. there is an actuator under the dash on the heater box. see if it is stuck yo may have to feel around for it it's electric. if it's bad it will have to be replaced or see if there is any power going to it....

The control unit that Blaze mentioned could also be the culprit since it helps determine whether the system blows hot or cold.

I have reset system will let you know if it works with in a few days

Ok. We'll be waiting.

Ok relearn did not work passenger side now blowing hot with ac on

Can you cycle the unit through the various settings and listen for the doors to actuate? Do they seem to be moving?

Hi.
I just had the transmission rebuilt in my Yukon Xl. I picked it up and noticed that the air conditioner does not cool on the drivers side. Everyother vent is receiving cold air. The driver side is pouring out heat. Could this be related to the transmission? How can this be fixed.
thanks

check under the dash for a vacuum or electric motoor. it will have a shaft connected to it. the door may have stuck or there is a vacuum line off, maybe under the hood on the firewall or under the dash or it's just not getting the power to itto move the motor. you may have to remove a panel to get under the dash.

Yes today it is working fine right know I might change both actuaries this week many they are both weak before changing the control module don't know what else to do. Need to fix before wife kicks me out of bed

Ok, let us know how it goes with the actuators. Without being able to see and touch it, those would be my guess as to the culprit,

Front ac ac and heat driving down road ac changes to heat could be drivers side passenger side or both winter has opposite effects

try pulling hvac fuse first for 60 seconds, then reinstalling and waiting 60 seconds then see if it works right, sometimes this resets actuators to work if electric it may also be your control panle hass gone bad but tha will need to be scanned.

This is a split zone heating and cooling in the front. The driver side only blows cold air, and the passenger side only blows hot air. no matter where the slide is at. Could it be the actuator? and if so which one? the temp actuator?

Your vehicle has two blend air doors. If you are referring to the blend door actuator, that is my first guess. They are located near the heater core box under the dash. Check to see if they respond when you try to adjust the heat / cold.

Let me know what you find.

I was wondering since both sides went out at the same time, is there something common? would both actuators fail at the same time?or is there also a common temp actuator? I will pull the cover and take a look and tell you what I find thanks

It's odd that both would go at the same time. Have you checked simple things such as fuses or power supplies?

hello again,
I removed the blend door actuator and manually moved arm side to side. I now have hot air and cold coming from drivers side, so I ordered the replacement. Does the passenger side have a seperate actuator as well? that side seems to only blow hot air. if so where is it located? thx jeff

Yes, both have their own actuator.

Where is the other one? Thx i only see one when i remove the cover

See if these pics help. One is the left and the other the right.

That's the same picture thanks though

Wow! I must have selected the same one 2 times. Did it help or do you need me to find the other?