Hey guys yesterday driving the jeep I noticed that my A/C stops blowing when I accelerate..As soon as I let of the gas a bit the A/C starts again, Its cold and everything but if im increasing in speed nothing comes out...Anyone know what this could be??? BTW its a 93..

Thanks in advance..

 

I had the same problem with my '98 Cherokee, and now it will only blow through the defrost vents. If you get an answer please let me know

 

When this happens sometimes it's a problem with the vacuum line that comes out of the firewall near the master cylinder.


Edit: Read this thread. It may help. https://www.cherokeeforum.com/f5/hva...ncluded-49071/

 

k thanks, ill check it out..

 

Keep us posted.

 

Seems like the Vacuum tank is under the right fender behind the bumper.
If its not hooked up you don't have consistent vacuum to operate the vent switches.
If its MIA get a new one and hook it up.

 

On all modern cars, when the vacuum system leaks the HVAC system defaults to defrost only. It is intentionally engineered into the system for safety reasons. It is also how you know you have a vacuum leak.

 

If the dash vents switch to the defrost only when giving it a lot of gas, then the one-way check valve for the vacuum line going to the tank in the front bumper may be toast. That was my problem. The vacuum escapes back into the intake manifold when the engine vacuum drops. Its a little round plastic valve in the tube going from the intake manifold to the firewall. Pull it out and blow through it. If there is no resistance in one direction, thats the problem. I bought a new one from Autozone for $4. I have a 1999 so hopefully its the same setup.

 

I’m guessing this is the price you’re talking about

 

My vacuum line on this piece keeps blowing off the nipple can that be caused by the check valve on the intake manifold being out?

 

Does anyone know the part number and source for the 1/4" HVAC check valve located near the fire wall in the vacuum line ? It's not the Dorman 47170 - that one is the check valve that comes off the manifold is too big. Thanks !

 

Here's my suggestion. Rather than continue to bump 10 year old threads asking for a PN, start your own thread. Include symptoms and how you determined the check valve is bad and why the one you bought doesn't fix it. Perhaps you overlooked something.

 

Inspect all this.