Another Electrical Thread!!

[Jimboslice]

Hey guys! I've been doing research, searching the forums and racking my brain recently!
I have an 02 yukon. Has computer climate control and rear controls. Rear controls I figured out, but the front has me stumped! Blower motor works up front, I believe i need to replace the mode actuator. I hear it making noise and I can kind of help it along so I'm going to do that. The temperature however I replaced with 2 dorman actuators and it still doesnt work. I finally get them to move and they move a little and stop then a little more and stop. It's almost like a pulse signal. It happens connected to the blend door or not, and with all 3 actuators! I'm stumped! Also, since I seemed this an electrical thread, another question is my windows. They work fine at all the doors except my master. Passenger front and driver rear wont go down via my master switch. If I put them down with the switch at the door i can put them up via my master. Just not down. If anyone could shed some light on my situations that would be awesome! Please ask if you need more information about my situation. Even call me a dumbass and point me to a solution! Anything helps!
Thanks in advance!

 

[Doubeleive]

you might need a tech2 or a scanner capable of checking the hvac system I just went thru a not the same problem but related and the tech2 will give a readout of the temperature the system is reading and a temperature desired, I had replaced the hvac control unit over the summer and everything worked fine till it got cold then I was getting heat up front and cold in the back unless I turned it all the way to 90, turned out it was the software on the head unit and it was looking for a reading from a rear temp sensor that I did not have and was making everything screwy I had replaced the actuator like you have and I would sit there and watch it move all the way to cold when I adjusted the temp by just 1deg. but in the meantime I was looking at the tech2 and seeing the temps it was reading and what all was happening. I pulled the sensors and checked those and harnesses for the correct 5v and everything was checking out. so a technical tool may help you in this situation

 

[Jimboslice]

Thanks for the input man! Yeah it barely moves but it does move. We hooked it up to a scan tool and it came up with "air control 3" and "temperature control 3" that's why I figured replacing the actuator would work and it has not. It just moves slightly from hot to cold. And it will move the same from cold to a notch above. But you can watch it pulse. It will go then stop then go then stop. Very strange. And like I said k have 3 different actuators I plugged in and they all do the same!

you might need a tech2 or a scanner capable of checking the hvac system I just went thru a not the same problem but related and the tech2 will give a readout of the temperature the system is reading and a temperature desired, I had replaced the hvac control unit over the summer and everything worked fine till it got cold then I was getting heat up front and cold in the back unless I turned it all the way to 90, turned out it was the software on the head unit and it was looking for a reading from a rear temp sensor that I did not have and was making everything screwy I had replaced the actuator like you have and I would sit there and watch it move all the way to cold when I adjusted the temp by just 1deg. but in the meantime I was looking at the tech2 and seeing the temps it was reading and what all was happening. I pulled the sensors and checked those and harnesses for the correct 5v and everything was checking out. so a technical tool may help you in this situation

you might need a tech2 or a scanner capable of checking the hvac system I just went thru a not the same problem but related and the tech2 will give a readout of the temperature the system is reading and a temperature desired, I had replaced the hvac control unit over the summer and everything worked fine till it got cold then I was getting heat up front and cold in the back unless I turned it all the way to 90, turned out it was the software on the head unit and it was looking for a reading from a rear temp sensor that I did not have and was making everything screwy I had replaced the actuator like you have and I would sit there and watch it move all the way to cold when I adjusted the temp by just 1deg. but in the meantime I was looking at the tech2 and seeing the temps it was reading and what all was happening. I pulled the sensors and checked those and harnesses for the correct 5v and everything was checking out. so a technical tool may help you in this situation

 

[Doubeleive]

I think there is a rear control unit that passes the information to the two rear actuators that may be the source of the problem, I am just going from memory but there should be a module right there at or near the rear hvac somewhere.

 

[Fless]

Isn't there a relearn procedure to reset the actuators?

 

[Doubeleive]

Isn't there a relearn procedure to reset the actuators?

there is but he replaced the actuator and it's still doing the same thing, I think I have read about the rear control module causing problems in the nbs before, basically if the actuator is good then the control unit may be the problem, not the one in the roof it is in the back on or near the rear hvac unit.

 

[Doubeleive]

this may be it
https://www.ebay.com/itm/HVAC-Contr...=item25e8f3f119:g:T2QAAOSwgslbJZki:rk:20:pf:0

 

[Fless]

Think the OP was having trouble with the front computer climate control, if I read that correctly.

 

[Doubeleive]

Think the OP was having trouble with the front computer climate control, if I read that correctly.

your right, I think the air control 3 threw me off

 

[swathdiver]

...another question is my windows. They work fine at all the doors except my master. Passenger front and driver rear wont go down via my master switch. If I put them down with the switch at the door i can put them up via my master. Just not down. If anyone could shed some light on my situations that would be awesome! Please ask if you need more information about my situation. Even call me a dumbass and point me to a solution! Anything helps!
Thanks in advance!

Again, these can be tested by a Tech2. I had the RR window switch go bad, the kids could put the window down but not up. I could put it up. Replaced the switch. A month later the LR window switch failed the same way. Same switch.

A Tech2 with regards to your AC will have internal BCM codes stored for what is going on and even why an actuator failed. If the actuators are working, or trying to work, then the control module would be the likely culprit but sometimes the doors themselves break which necessitates taking the whole dash apart to make the repair.