Hey Folks,
Sorry I’ve been out of touch for a while…health reasons, but I’m slowly coming back.
I have a 98 Plymouth Grand Voyager that I just got started after sitting dead for 7 months. The LED lights on the climate control buttons (A/C, Defogger, etc.) flash on and off for several minutes before turning off. They stay off but once I’m on the road but come back on once the car is turned off and started again.

Any ideas what it means and how to fix it?

There’s nothing in the Owners Manual.

Thanks,
Big Dan 58

I have not tried this method myself, I just copied it years ago in case I had the same problem.
Let me know if it works.


Here you go:

#321 of 642 Re: AC/heating lights on dashboard [rebellady1964] by crackerjax May 30, 2005 (3:36 am)
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Replying to: rebellady1964 (May 15, 2005 5:22 am)

I had the same problem and the Dodge House where I lived wanted 500 dollars to fix it! I found someone on the internet who helped me out and I pass this on to you and others to save you some big money as this you can do for free. Here is what you do:
All you need to do is start your van. Then slide your temp lever all the way to full cold. Then turn the Mode Control to the one that sends air to your face only. Then turn the 'blower switch' to all the way to full. Now go to the leftmost three buttons. Press the top one (rear wiper on constant) and the bottom one (rear wiper washer fluid). Hold these two for a few seconds. Once the lights come on solid then begin to flash, you can let go. The AC will now calibrate. You will feel the air blow out of all the different zones at different intervals and see lights come on and go off. Then after a minute or two the top button you pressed will be slowly flashing. This means it has been completed. Press the last flashing button and you are done. Turn off the van and started it back up and see now you don't have those infernal blinking lights anymore! Hope this helps! Oh, be careful with the battery, it is very touchy on Dodge Caravans and can blow out any electrical thing so it is better to take the battery out and charge it and don't charge it directly. One guy mentioned it blew his on board computer just accidently touching the wrench and grounding the battery so be careful with the battery

Those buttons have their own "computer" of sorts... it's the HVAC control system that's causing them to blink. Apparently, they will start blinking if you're getting a bad battery too, so the blinking is not always related to the HVAC system itself.

The blinks that it displays after running several tests indicate an HVAC DTC (Diagnostic Trouble Code) that tells a technician what to "fix".

You can probably get a look at what each code is and how to read it at your local dealer. They can also tell you how to manually reset the system. Resetting the system is always the first thing to do, b/c that DTC may be false. If it re-appears, there is more than likely a problem.

If I get the codes from the dealer this weekend (mine is flashing too, 2000 Caravan Base) I'll post them up with the procedure to check/reset them.

I'm not sure, but I also believe it can set codes in the event that the rear wiper/washer system isn't working properly. (No matter for me, I'll be taking it out anyway.)