i have a problem when i accerlerate or cruising at high speeds in overdrive. my a/c starts blowing from the vents to the defrost. it's really anoying. i was wondering if anyone has had this problem and has any info on this problem. i think i have a vacum leak some where. i do not know how to find it. any info is greatly appreciated.

 

I dont know a terrible lot about it, but you can get refrigerant with UV dye in it. Try running that through and using a UV light to see what you can find.

 

You are losing vacuum to the A/C servos under the dash.

There is a vacuum reservoir below the engine air cleaner housing that is supposed to maintain vac to the A/C system even when the engine vacuum drops as the throttle is opened. The reservoir has a check valve on the port that connects to the engine.

If you have a bad check valve, cracked reservoir or damaged vacuum line, you will get this defrost default symptom.

Look the reservoir over for problems, then check its two vacuum lines that go to the engine and A/C box on the firewall. There is also a small chance that the vacuum leak is under the dash.

 

If you have an aftermarket stereo, its a probability it was disconnected during install. Ive done it.

But it could be cracked or something too, but most likely, like bob said, its behind the dash on the firewall.

 

I have that same problem, and I don't want to scare you but when I pulled mine out, I found out that the vacuum canister they are talking about was full of mud and water. the bad news is that the lines all the way up to and including the ac control panel had small amounts of mud in it. this is due to the vacuum canister also being connected to the vacuum hubs and one of the seals went bad and sucked up mud and water into the canister.
I am not sure if you are having the same problem, just thought I would let you know what happened to mine.

 

any diagrams on hoses behind dash? my ranger seems to want to turn off when i turn on the defroster, but works fine on panel and floor?