I have a '98 Intrepid ES that I love, 127,000 mies with so far no problems, knock on wood. But this year the automatic climate control started acting up in heat mode. I never use the auto feature, just set it on 68, floor vents, and modulate with the fan. Then one day, no heat. I womped it up past 90 to HI, still no heat. Then at one point it started blowing hot again. The next day, nothing. And it was a balmy -13 that day.

This may sound weird, but a couple times I drove it on the freeway for about 90 miles each way, and I swear that whether I got heat or no heat depended on whether I went over a bump or not. My wife and I started laughing about it after going over particularly rough expansion joints that "well, there goes the heat" or "oh boy, the heat's back on!" Coincidence? I'm not sure.

I have several other money pits sucking my wallet dry right now so I'm limping the heater onward toward spring (and hope it doesn't affect the A/C) but I'd appreciate some ideas of what might be wrong.

 

check the conections under the passenger side dash there are two connectors going into a heat sensor or it could be a bad switch.

 

If an ATC system: set tem to 75, press and hold 3 of 4 top row buttons at the same time (all but the ac button). Display will blink. When it stops, if any number other than 75 displayed, let me know. Other than that, I'd say a blend door malfunction or sticking.

 

Either I'm being really dense or don't have the same system as you're referring to. My '98 has ATC and the dash presentation is a round **** for the fan, and to the right of that five rocker-type buttons that do different things if you push them up or down. Left to right are Auto/Off, Temp, AC/Recirculate, two buttons for where you want the air to blow, and the last one runs the front and back defrosters.

I set the temp at 75 and pushed any three except the AC one but the system just did whatever the buttons said (like the temp started rising, it went to Auto, etc.

Does it matter if the car's running or not when you do this?

 

see my post in your other thread

 

Yes the car must be running. Before you reset the codes (by disconnecting the battery) try to get the code (if any in memory). It sounds like your control head is different than mine, but the buttons should be the same. They are "floor", "mix", & "defrost". Also go to the top of the second gen forum and see the post "the holy grail". It is a link to a 2002 trep service manual. See pg 24-4 (all of section 24 would help you with your issue/knowledge).

Kurt