Heater not working

[hobber]

The heater on my '96 Altima is not blowing any hot air. I replaced the thermostat yesterday, and for a couple hours all it would blow is hot air. Late last night the original problem resumed. Only blowing cool air. AC works, heater does not. Help.

[hobber]

PS. The Altima has nearly 100K miles. I live in the Phx, AZ metro area. Have performed all periodic maintenance.

[hobber]

Now the heater is working, but I can't get it to blow any cool air when the AC is on. The AC clutch responds when I push the AC botton on the dash, but light does not come on. All other buttons on the dash control seem to work, except the temp. control slide/lever. All of the blowers are working.

This appears to be an intermittant problem. As I mentioned earlier, sometimes it blows very cold air and other times it blows very warm air. Always one or the other.

[TX240SX]

It sounds like the switch or cable used to work the vent between the a/c coil and heater core is not working properly. If you have a slide knob that operates the vent door between them check the cable. If it is electronic you may want to try bridging the connections to see if you can get it to work. If you can you will need to replace the a/c contol panel. Hope this helps

[drjohn]

You cuold have a problem with the air mix door motor if you switch the temp from cold to hot and the mode door selector from one setting to another and listen to the dash you might hear a steady clicking from the dash from a bad mode door motor. Possibly from behind the glove box area. This may stick from full hot to full cold mode they have plastic gears in them that strip out.

[hobber]

drjohn, I think you have isolated the problem. I do get a click sound when I switch temp. Where is the air mix door located? Is this an easy diy job? If not, how many hours will a shop charge? Thanks for your inputs.