I've been having problems with battery drain on my 2000 convertable. In an effort to find that problem, I've created an even greater problem.

The HVAC controls are dead, the tire monitor system does not work - the message display reads: "Service tire monitor system" and "Service Vehicle Soon" and the key fob no longer works. Pushing the "reset" closes out the messages until the next time the ignition switch is turned on. The car runs fine and everything else is functioning.

The fuse for the HVAC system is OK.

Any suggestions?

I've resigned myself to having to use a battery maintainer if the car is to sit more than a couple of days. I did determine that the "sleeping" amperage drain is about 600 miliamps. I pulled every fuse, relay and circuit breaker (one at a time; doing this is probably what caused the above) and the drain never varied from the 600 miliamps. When I bought the battery maintainer from one of our advertisers the person on the desk said he had a '97 that would run its battery down in about 5 to 7 days. He attributed the drain to the security system in the car, but he was not certain.

Several months ago (the car "rested" during the winter months) one of our members thought that the drain should be less than 100 miliamps. So if anyone out there has some ideas I'd love to hear what they are!

 

The ECM and various computers on the car cause a small constant drain -- just get a battery tender. As to the other problems, note that there are on certain circuits very small breakers that typically re-set after the power is disconnected and reconnected (or the key is pulled out and reinserted), not just fuses. It's been a few years so I don't remember the details anymore. However, you might have a broken ground lead or any number of things including a bad breaker, but I'd suggest taking it to a pro.

 

Thanks for the info, but would still like to know which (if any) relays or circuit breakers are in the tire monitor or HVAC circuit(s)