A/C Issues

[jakcol997]

Hey guys! Dilemma here. My back a/c on my 99 Yukon 4dr works intermittently, and only works on high.. I just replaced all 3 back relays, because two of them were burned to a crisp. I thought by doing this, that would fix the issue, but it hasn’t.. I checked the rear blower motor resistor (I believe (( looks like a little circuit board with metal springs on it)), and it looked fine, but idk what else it could be. Also, my front a/c has crazy low air output, and I cleaned the condenser by taking the blower motor out, and cramming my arm in there! Do you think a new blower motor would help that? They’re only like $45 bucks. Any help would be MUCH appreciated

 

[PG01]

Either the rear switch control or the rear resistor even tho it ‘looks good ‘

And did you replace the front resistor? Try running blower without it being in the box? See if it changes speeds. Make sure you have all speeds up front.

 

[jakcol997]

Either the rear switch control or the rear resistor even tho it ‘looks good ‘

And did you replace the front resistor? Try running blower without it being in the box? See if it changes speeds. Make sure you have all speeds up front.

Would the front resistor have any effect on the back? The front by my radio control has all settings, but both rear a/c controls only work on high! I’ll have to go the pick and pull and grab a couple and see if they’re any good! Thanks!!

 

[79jasper]

Blower resistor only affects the blower it is hooked to. Front is front, rear is rear.

Sent from my SM-N960U using Tapatalk

 

[PG01]

Would the front resistor have any effect on the back? The front by my radio control has all settings, but both rear a/c controls only work on high! I’ll have to go the pick and pull and grab a couple and see if they’re any good! Thanks!!

Blower resistor only affects the blower it is hooked to. Front is front, rear is rear.

Sent from my SM-N960U using Tapatalk

no front resistor only does front blower...rear only rear.....As @79jasper said... thanks fir clarifying jasper.

I misread and thought you said the front blower wasn’t working on anything but hi...But now that I reread and see your front and rear controls for the rear blower work on high only it probably is the rear resistor....
Tough to diagnose these things over the internet but it’s 1 of 4 things... resistor, blower, switches, wiring.
I’m going out on limb here and say the wiring is prob ok as are the switches too because both do the same thing. That leaves resistor and blower.... cheapest is resistor then blower...9x out of 10 its the resistor...

 

[jakcol997]

no front resistor only does front blower...rear only rear.....As @79jasper said... thanks fir clarifying jasper.

I misread and thought you said the front blower wasn’t working on anything but hi...But now that I reread and see your front and rear controls for the rear blower work on high only it probably is the rear resistor....
Tough to diagnose these things over the internet but it’s 1 of 4 things... resistor, blower, switches, wiring.
I’m going out on limb here and say the wiring is prob ok as are the switches too because both do the same thing. That leaves resistor and blower.... cheapest is resistor then blower...9x out of 10 its the resistor...

Awesome! Thank you so very much! I noticed when I turn the rear a/c on, sometimes it doesn’t engage at all, and if I smack it, it’ll turn on!! I’m over this, haha it’s almost 100 degrees every day, and I want to be comfy in my car haha, next would be why my front a/c doesn’t hardly blow at all after cleaning the condenser thing.. maybe a weak front blower motor? It whines in the winter time when I turn the heat on...

 

[79jasper]

Smacking the motor or the control panel?
If the motor, the motor brushes are worn.

Sent from my SM-N960U using Tapatalk

 

[jakcol997]

Smacking the motor or the control panel?
If the motor, the motor brushes are worn.

Sent from my SM-N960U using Tapatalk

The motor!