Compression Ignition Addict
Join Date: Apr 2013
Location: Thomasville, Georgia
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Another defrost issue thread...
I am not just posting this without thoroughly reading and searching not just our forum but many others and my problem still persists so I do need your expertise!
The truck with these issues is a 00' 2WD...
Finally got the A/C system fixed after being broken for 1+ year (by fixed I mean it took the entire mehanical system, condensor, evaperator, dryer, compressor, manifold lines, clutch fan, etc...) Everything works very well except for the dang old vent failure to defrost that seems to happen to everyone at some point.
Here is the run down of symptoms and what I have tried.
Symptoms: ONLY after driving for 10 min+ the vent air will slowly change to defrost only, if I turn the function selector to the "OFF" position and let it sit for 30 seconds then turn it back to Vent, A/C, or Max A/C it will work good again for a couple of minutes and then begin the process all over.
Fixes already tried:
1.) I have made sure the vacuum pump is operating properly, it turns on when I disconnect a vacuum line and from a completely empty vacuum resevoir it only takes around 90 seconds to fill the system and turn back off.
2.) I have used the soap and water method to check ALL the HVAC lines, from the vacuum pump and resevoir into the dash and even tested the vacuum actuators under the dash and have found no leaks.
3.) I have replaced the function selector switch as I found a slight leak inside the vein for the vacuum control.
4.) I have replaced the EGR and MAP sensor lines and made sure they were clamped with no leaks.
5.) It is 2WD so there are no hub lines to be concerned about...
The problem is still present though and with 97 deg. days on me here in south Georgia I want this resolved!
So what am I missing? I read somewhere on some forum that the EGR solenoid could be leaking? or MAP sensor? those arent expensive to get but I am tired of trial and error as the test drives to duplicate the problem take time!
P.S. When I replaced the MAP/EGR lines I found a hole in the MAP line and after that replacement I can feel a difference in vent system (you can tell the vacuum doors are closing all the way when first used) and I can tell that leak was a major part in this ordeal but after use the system still leaks back down.
Thank you for any help guys!!
00' F350 CC DRW still pushing well past 300K: 6637, GTP38R, 5.6k mod on turn dial, superchips, trans command, Torque pro on Galxy S2 for PID monitor, OD lock, 4" straight pipe, condensor cooler w/electric fan, watersprayed intercooler, 08' taillights, 05' headlights, BD valve body kit, all door locks foiled, full LED exterior light kit, and the list is still growing.
Last edited by ThomasvillePavers; 06-11-2013 at 05:01 AM.
Reason: Spelling error