A/C blowing high to low

heath223 · 06-20-2010, 04:42 PM

My A/C in my 98 Explorer has started blowing slower when the engine revs. Example... I will have the A/C on high and it is blowing high then I start up a hill or pull off fast from a stop or just accelerate pretty good wile driving and the air flow slows or stops and a couple times it has even started blowing out the defrost vents.

I had the intake manifold/gasket replaced 6 months ago so could it be an issue with vacuum (if the controlls for the A/C work off vacuum)?

**Maniak** · 06-20-2010, 04:45 PM

This is probably the thread you want..

http://www.explorerforum.com/forums/...d.php?t=192842

~Mark

heath223 · 06-20-2010, 04:58 PM

Thanks for that but mine is blowing from the vents and I can switch from vents to defrost fine it's just without making a change my fan blows slower or either something is going on with the vent selection and some air is being diverted elsewhere or to the defrost? but I have seen a couple times where it definatly starts blowing out the defrost then once I ease off the gas it will divert back to the vents.

**Maniak** · 06-20-2010, 05:10 PM

If the Fan is really slowing down I don't have an idea...

If the air moves from the dash to the defrost when you lose vacuum then the vacuum ball or check valve must be having an issue.

~Mark

heath223 · 06-20-2010, 08:40 PM

I did check it and it is not the motor slowing down. When the air decreases at the vents I can feel a little air coming from the defrost. I guess I need to start checking for vacuum leaks? Could this have anything to do with having the intake manifold replaced, other than if they damaged a vacuum line when they changed it.

06-20-2010, 04:42 PM	#1
heath223 Wannabe Elite Explorer Columbus, Ga 98 xls, 04 xlt Join Date: Jan 2010 Posts: 7 Vehicle Specs (Original Poster)	A/C blowing high to low My A/C in my 98 Explorer has started blowing slower when the engine revs. Example... I will have the A/C on high and it is blowing high then I start up a hill or pull off fast from a stop or just accelerate pretty good wile driving and the air flow slows or stops and a couple times it has even started blowing out the defrost vents. I had the intake manifold/gasket replaced 6 months ago so could it be an issue with vacuum (if the controlls for the A/C work off vacuum)?

06-20-2010, 04:45 PM	#2
Maniak Moderator-Stock 91-94 Vail, Arizona 1992 XLT 4x4 Join Date: Feb 1999 Posts: 10,742 Vehicle Specs	This is probably the thread you want.. http://www.explorerforum.com/forums/...d.php?t=192842 ~Mark __________________ Click HERE to see our Explorer Specs

06-20-2010, 05:10 PM	#4
Maniak Moderator-Stock 91-94 Vail, Arizona 1992 XLT 4x4 Join Date: Feb 1999 Posts: 10,742 Vehicle Specs	If the Fan is really slowing down I don't have an idea... If the air moves from the dash to the defrost when you lose vacuum then the vacuum ball or check valve must be having an issue. ~Mark __________________ Click HERE to see our Explorer Specs

06-20-2010, 04:58 PM	#3
heath223 Wannabe Elite Explorer Columbus, Ga 98 xls, 04 xlt Join Date: Jan 2010 Posts: 7 Vehicle Specs (Original Poster)	Thanks for that but mine is blowing from the vents and I can switch from vents to defrost fine it's just without making a change my fan blows slower or either something is going on with the vent selection and some air is being diverted elsewhere or to the defrost? but I have seen a couple times where it definatly starts blowing out the defrost then once I ease off the gas it will divert back to the vents.

06-20-2010, 08:40 PM	#5
heath223 Wannabe Elite Explorer Columbus, Ga 98 xls, 04 xlt Join Date: Jan 2010 Posts: 7 Vehicle Specs (Original Poster)	I did check it and it is not the motor slowing down. When the air decreases at the vents I can feel a little air coming from the defrost. I guess I need to start checking for vacuum leaks? Could this have anything to do with having the intake manifold replaced, other than if they damaged a vacuum line when they changed it.