My heater blows hot air even when it is turned off also my ac wont work
I just repaired one with this problem. The selector knob for heat/cold was cracked inside where it slides onto the stub that sticks out of the dash. It felt like it was working, but really it was in a bind and just felt like it was working. Also, there is a selector that diverts the hot air into the cabin, or it lets outside air in, or it recirculates the cabin air. I think the selector knob is your best bet. Mainly because the heat is working and the air is not. If it happened to break while on heat, the ac will not work when the heat is on. You can try to switch the other selector to defrost and see if the ac compressor kicks on. There is also a fuse for the compressor, so check that. If all that checks out fine, check out the diverter in the dash. Usually this is vacuum operated, sometimes electric. But, if it is vacuum, the problem may not be the unit itself. It can be a vacuum leak somewhere under the hood that is leaking so much vacuum that there is not enough left to operate the other accessories. Sometimes on older vehicles, the vacuum hose will split where it is slid on a connection. The connection, or tube is usually somewhat larger than the hose and being in a stretched position for years and exposed to the engine heat, it will finally fail. Most times when this happens, you can take the end of the hose off of the barb fitting, cut it off just above the split, and install it back on the connection or fitting. I would check all the hoses in the vicinity of the engine and look at the ends of all of them. Your engine may still run, but that is because there are "limp" modes built into the computer controls that allow the engine to run without some things. My first thing would be to check out the dash selector, just pull the knob off and you can turn the stub with a pair of pliers and see if that does it for you. Then, you can check the fuses, Switch on defrost and see if compressor kicks on. If it does, check vacuum lines. The part in the dash hardly ever needs replacing. I have some thirty some odd year old trucks here and that is about the only part that has not been replaced on them. Then, if all that checks out, are you sure the charge is ok on the ac? The low pressure switch, which is plumbed into the ac system, may have the ac shut down. But, make sure all the other things are checked out first. On a Ford, you can un plug the low pressure switch and jump between the two wires with a jumper wire and see if the compressor kicks on. This can be done without the engine running, you will hear the electric clutch on the compressor engage when you jam the jumper wire in with the key on. Be sure to un do it shortly because will drain your battery, and if it is on a low charge situation, don't run the compressor without enough refridgerant.
Jul 11, 2010 |
2002 Ford Explorer