Defroster blowing but wont switch to floor or vents?

[CROOZ1N]

I found this one the other day after getting my vette back from the shop. The AC was blowing but it was blowing out the defrost vents at base of windshield. At first I thought it might be the vacuum distributor under the dash but then I thoughtthat I'd check where the work was done first. So I pulled the injector cover off the passenger side and found a broken line on what I later found out is a 2 way check valve.I found one at Advance and replaced it for $3.29 and now the doors shift better than ever.

Maybe this will help someone else out later.

 

[LT4man]

You are right! That is the 1st place to look when encountering that problem. Those check valves do not last forever! :L

Actually, any vacuum leak would contribute to that problem. Also, if your cruise stops working, check all vacuum connections.

AFTER REPLACING YOUR CHECK VALVE, DON'T FORGET TO SAVE THE !