95 conversion van ac blows in front but warm air blows out rear vents why? on 1995 Ford E-150

when van is pulling the air flow in front changes from front vents to defrost vents.Have checked rear fuses at loss help.

Asked by for the 1995 Ford E-150
1 answer 2 comments
REAR UNIT HAS BLOCKAGE PROB. EXPANSION VALVE IS WHY IT BLOWS WARM AIR.
VACUUM LEAK PROB. UNDER HOOD IN SMALL VAC. TUBE OR CHAMBER IS WHY SWITCHING
VENT TO DEFROST. SEE MECHANIC.
what could have caused the blockaged? This happened about 3 mo. ago. Is there someway I can check without going to mechanic am on a fixed income. Thank You very much.I will show this to my son and check this out.
AN INLINE FILTER IS AVAIL. AT NAPA OR POSS. OTHER PARTS STORES.
HAD TO PUT ONE IN MY CHEVY. AFTER CLEANING IT 2 TIMES I GOT
TIRED OF THAT, THE FILTER WORKED FOR ME. AS FOR YOUR VACUUM
LEAK LOOK FOR SMALL PLASTIC TO RUBBER HOSE GOING INSIDE
THROUGH FIREWALL. IT IS PROB. BROKEN OR UNHOOKED.