98 Jimmy blowing HOT air out AC vents with AC on !!

[Heypops]

I have a '98 Jimmy 4x4, 156k miles, Electronic Climate Control.
Drives great and runs great!!

Recently started blowing HOT air out of AC vents even with AC ON & turned to 'cold' on electronic controls.

Have checked all vacuum hoses and OK. Vent selector works correctly & well, as will blow HOT air out of floor or dash or defrost as selected on dial.

Have read many threads as to needing to change out 'heater blend door or gate', which means taking dashboard off the car.....YIKES !!!!


How do I do get to the 'blend door' or 'actuator' w/o completely removing the dashboard??

Question:
what is best way to diagnose the cause of continuous HOT air from the vents and best way to fix this problem.
Do I need to remove the entire dashboard? Is there a shortcut to the getting at the heater box/actuator?

thanks again to all !!!!

 

[Molson02536]

I have a '98 Jimmy 4x4, 156k miles, Electronic Climate Control.
Drives great and runs great!!

Recently started blowing HOT air out of AC vents even with AC ON & turned to 'cold' on electronic controls.

Have checked all vacuum hoses and OK. Vent selector works correctly & well, as will blow HOT air out of floor or dash or defrost as selected on dial.

Have read many threads as to needing to change out 'heater blend door or gate', which means taking dashboard off the car.....YIKES !!!!


How do I do get to the 'blend door' or 'actuator' w/o completely removing the dashboard??

Question:
what is best way to diagnose the cause of continuous HOT air from the vents and best way to fix this problem.
Do I need to remove the entire dashboard? Is there a shortcut to the getting at the heater box/actuator?

thanks again to all !!!!

You don't have to take the dash out of the jimmy to get to the actuator. You can get to it by removing your glove compartment and going through there. just make sure you disconnect the battery to ensure you will not get hurt from the ar bags.

Soon as you remove the glove box, you can access the actuator on top of the heater box towards the center of the Jimmy.

Hope this link will help you understand what i mean by behind the glove box. http://www.justanswer.com/gm/2sfiq-need-know-blend-door-location-98-gmc-jimmy-please.html

Molson02536

 

[dirtclod]

So Heypops, we assume you checked that the a/c compressor is working

 

[Heypops]

Yes to Dirtclod, my AC is on and working!

Many thanks to Molson02536 !!! Great link to see the parts!

Just had my cataracts removed, so will wait a few days before getting upside down to work on the dash and actuators. But cannot wait to get at it!!

thanks again guys !!
pops!!

 

[Heypops]

NEW INFO TO CONSIDER on Jimmy AC blowing hot air

NEW INFO: While working in the car today with motor and AC working....had several cycles of COLD AIR then HOT AIR, with each cycle lasting about 10-15 secs. Then the cycles stop and reverts to the problem of steady blowing hot air.

QUESTION: Any way for me to determine if the problem is caused by a Mechanical or Electrical (sensor) failure?

thx to everyone !!
Happy New Year !!!

 

[dirtclod]

The first thing a shop would do is to put a set of gauges on the a/c system. It's the only way to tell if you have a low refrigerant charge. A $50 set will work just fine. If the charge looks good, then you look to the safety pressure switches.

 

[Heypops]

Thanks to Dirtclod for the idea to check the AC charge.
I'll chk the pressures and get back to the forum.

BTW, I'm learning quite a bit as I go thru the process of getting at the AC/heat system for this jimmy. Still driving it also!!

thx again !!

 

[bluefleetwood]

This may be a stupid question, but have you checked you Heater Control Valve. If its stuck in the open position, hot water is flowing through your heater core constantly.
Just a thought.