Auto Air Conditioning & Heater Repair: directional control, gmc safari, safari van

Question
On a 1996 GMC Safari Van, with dual system a/c, all of a sudden, I stopped getting air through the front vents, except the side defroster vents.  Rear system works fine.  I replaced the control head in the dash, to no avail.  Can you help?

Answer
Steve,
The 96 safari used a vaccuum system to open and close different doors so that air would be routed in a particular area. The rotary switch that you replaced was just the beginning of the system. This tells the vaccuum control manifold which lines to vent and which lines to pull vacc. on. In turn opening and closing different doors in order to route the air to where you want it. Being that it works in no other area than your side defrosters, that tells me that one of two things happened. Either the vaccuum source hose has come off of the vaccuum control manifold, or the diaghram inside the VCM has gone bad. Either way, I would recommend that you take it to a reputable shop to have htem diagnose and repair. This can turn into a rather in-depth replacement when doing it out of a garage. Alot of vehicles require taking the dash apart.
I hope that this helps you at least a little bit. If so, please remember to rate this answer. Thank you for the question, and good luck in everything.