AC Blowing Thru Defroster
Thread Starter
Drifting
Joined: Aug 2004
Posts: 1,519
Likes: 0
From: Bedford TX
St. Jude Donor '06-'07
AC Blowing Thru Defroster
Most cars I have owned do not blow cold air through the windshield defroster vent unless I have selected defroster setting. My 98 blows up no matter what setting. This does not seem normal. Or am I going crazy. (But that is beside the point.)
Thanks for the helpful responses.
Thanks for the helpful responses.
Melting Slicks
Joined: Jun 2001
Posts: 3,123
Likes: 3
From: Orland Park Illinois
St. Jude Donor '06-'07
I'm far from an expert, but, it sounds like a vacuum problem. First, check the fuses to make sure all is OK. Then I'd remove the battery and the tray. Look for signs of battery acid under the tray, on the wiring harnesses and corresponding areas. If there's signs of acid, it's a pretty good bet the acid has melted the vac line. Trace the black plastic vacuum line that runs from the rear of the engine, under the battery tray and goes to the vacuum canister i/s the right fender. Also check for the vacuum line coming out of the canister going into the dash. This isn't EZ to do as the vac line is wrapped up within an electrical wiring harnesses. The acid quickly eats up the plastic vac line. If battery acid is the problem, you'll be damn lucky if thats the only damage you encounter. Sorry I can't help more. Let us know the out come of the porblem once it is solved. Good luck... 
Burning Brakes
Joined: Aug 2000
Posts: 889
Likes: 0
From: DFW tx
My '98 doesn't blow thru the defroster vents.
Have you had the intake manifold off lately? There is a very small hose that attaches to the back about the size of one of those straws that comes on a WD-40 can. I believe this controls the vent doors.
Have you had the intake manifold off lately? There is a very small hose that attaches to the back about the size of one of those straws that comes on a WD-40 can. I believe this controls the vent doors.
Le Mans Master
Joined: Sep 2003
Posts: 6,276
Likes: 227
From: Farmington CT
Cruise-In VII Veteran
here it is
1. ck vac hoses under batt for acid damage(can access thru aft fender liner)
2. clear codes, maybe this should be #1
3. ck vacuum hose behind manifold
4. ignition switch sometimes messes up hvac
5. if in n.east stop by, these hvac probs seem interesting
1. ck vac hoses under batt for acid damage(can access thru aft fender liner)
2. clear codes, maybe this should be #1
3. ck vacuum hose behind manifold
4. ignition switch sometimes messes up hvac
5. if in n.east stop by, these hvac probs seem interesting
