[olopezm]

Hello Mark

That happens because of a vacuum leak, if the system does not detects enough vacuum it will revert back to defrost mode, that way "you might be freezing but at least you can see in the winter" as someone said before in the forum LOL. When you're going uphill or as you step on the pedal the vacuum at the engine decreases and the VACUUM RESERVOIR provides the stored vacuum needed for the AC system.

Now onto the vacuum leak, I have the same problem with mine, I already found where the leak is, but since I haven't had enough time I haven't found the exact place where I should connect the loose hose. It is located at the back of the plastic intake manifold it's a red colored hose you can easily trace it if you put your hand at the back of the manifold passenger's side it has a small check valve (white and black colored) which some other users have had problems with. This same hose goes from the intake manifold to the check valve which has a rubber tee and from there it connects to the firewall and to the vacuum reservoir under the windshield cowl, this is the point where the hose on mine was disconnected but I still need to take the cowl apart in order to find the spot where it should be connected.

If you have the same problem as me and you decide to take the cowl off I would really appreciate if you could take and upload some pictures, other than that you won't need to take anything apart and you can easily fix your problem.

Best regards,

Oscar.