Why do the lights on the heater control unit continually flash on a 98 caravan?

Answer 1

The BCM (body control module) has found an error. Most often low Freon level for the air-conditioner. you have to put the BCM through diagnostics to clear the error. A dealer here wanted $80.00 to do it. Here is the way you can do it. On the left side of the A\C control panel hold down the top and bottoms buttons (the rear wiper and rear washer button) with the engine running, high blower, panel, full cold (both levers if so equipped). When the lights on the panel come on solid and then start flashing release buttons. It will take about 2 mins or less for it to calibrate. If only the top left button is flashing you are done. Press that button once or restart van all function should be normal.

ADDED: In case of continued Problems:

Often, after doing these tests for the first time, the Cool Down Test fails, and the A/C and the Recirculation indicators flash simultaneously (though, just these two instead of the four.) Simply run the Cool Down Test independently by pressing simultaneously the A/C and the Wash Buttons. Hold for 5 seconds, and allow the test to run.

This may take more than a few runs to finally set. Mine worked when I ran the test as soon as I started the car the next time (after the car had cooled off completely overnight). When all lights go out except for the Rear Wiper, push the Rear Wiper to exit. Success!

Some have suggested turning the compessor off and running the car for 15 minutes previous to the Cool Down Test. This did not work for me. But it is true that if the compressor is cold (with condensation), the Cool down test will usually fail. Try, try again. If your A/C compressor is in good condition, it will eventually set. If nothing seems to work, your A/C might be have a problem.

WHY don't the manuals come with this information??

Hope I have helped you.