I recently picked up a '98 STX. The air blew real cold yesterday, now it blows HOT today???? Is there anything simple I should be looking for? Fuses?Relays?If so what # in the fusebox would they be?

 

Sounds like the infamous blendor problem, widely discussed here. I would say a low charge of a/c juice, but the compressor cycles on/off frequently then and it will blow outside temp usually. Hard call, it could be more than that for fun. Surely others will elaborate here soon.

 

Blend door or blend door actuator. If it was "real cold" yesterday, it's likely the A/C system is functioning normally. Probably the blend door area that's misbehavin.

 

It also blows hot with the dial set to any setting, and the temp. control set on cold. Is there any way to check to see if it's the blend door? I do hear something changing when I adjust the temp. control from cold to hot, but the air still blows hot!

 

First thing to do is get some gages on the system to see if you have the proper level of fridge in it. The system probably has a leak and who ever you bought it from knew that and charged it up before you picked it up.

 

I had the exact same problem on mine when I bought it and it was the famous broken blend door, mine would blow hot air all the time even with the switch on ac cold air, a blend door is about $30-$40 from a dealer and if you have them put it in you will pay out the butt for it or you can do it yourself and save the cash for more gas

 

The compressor is working, and the evaporator on the firewall is cold, and dripping wet with condensation. The box in the passenger compartment floorwell, just below the glovebox feels cool also. Sounds more, and more like a blend door problem to me. When I put my ear down by the boxes, and turn the temperature control ****, I don't hear anything moving at all. Should I not be able to hear the actuator?

 

I cant remember if you can hear it but it seems like you should be able to, to find out if it was the blend door on mine before tearing the whole dash out I took 2 or 3 screws out that hold the actuator up, I pulled the actuator strait down and there was plastic pieces of the blend door that fell out so I knew that was it, after I tore the Whole dash out and replaced the door that fixed the problem. Hope this helps

 

If you can't hear the actuator, it may be that (or maybe both). If you release the glove box door (it's easy), you can fold it down without taking it off. The blend door actuator should be straight ahead up high. It's electric so you should be able to hear it and feel it when you put your hand on it. I don't think you should have to have the truck running- only ign. in on position. Correct me if I'm wrong.

 

Thanks for all your help guys!