2004 GMC Safari Rear Air

BROWNC

MEMBER
2004 GMC SAFARI
6 CYL
AWD
AUTOMATIC
91,000 MILES

The front air works great, but the rear does not cool. The coils in the rear where the air circulates do not seem to cool at all and the line near the rear under the car does not cool but just a little.

Friday, August 7th, 2009 AT 9:50 PM

7 Replies

2CARPRO JACK

MECHANIC
11,533 POSTS

If the rear gets a little col, but not cold it may be a tiny bit low on charge (134a). To properly determine this, a set of pressure gauges need to be used to se where exactly the system is at. When you change temp for the rear unit, does the blower sound change tone? If pressures are good it may be the blend door inside the rear plenum not moving all of the way or having an obstruction keeping it from closing off the heat. To verify this you need to remove the interior side panel and acess the HVAC plenum

SPONSORED LINKS

Was this

answer

helpful?

Yes

Monday, August 10th, 2009 AT 7:50 AM

BROWNC

MEMBER
3 POSTS

Thanks for the info. However, it was charged with no change. I didn't understand about the heat as it is a stand alone with no separate temperature adjustment. Just works with the front A/C and uses a separate blower control to turn the rear air on.

Was this

answer

helpful?

Yes

Monday, August 17th, 2009 AT 9:39 PM

2CARPRO JACK

MECHANIC
11,533 POSTS

So it doesnt have rear heat/air?

Was this

answer

helpful?

Yes

Monday, August 17th, 2009 AT 11:43 PM

BROWNC

MEMBER
3 POSTS

Correct, it does not have rear heat, just rear air.

Was this

answer

helpful?

Yes

Tuesday, August 18th, 2009 AT 9:15 AM

2CARPRO JACK

MECHANIC
11,533 POSTS

Was it charged by a shop with gauges or a DIY kit? I would love to know the pressures. The rear evap core probably has an expansion block that isnt working, which would keep it from getting cold just in the rear unit