Chrysler Repair: Draining/dead battery 2000 Chry 300M, 10/12/05, toggle switches, heat sensors


Question
Thanks for your instructions, my son followed them and identified two fuses where the draw was occurring.  I returned to my mechanic who then attempted to follow the draw to its source(s), unsuccessfully.  To save time and money I authorized the installation of 2 toggle switches on the center console next to my right leg which when switched off cut power at the fuse box to my accessories and interior lights. When tested in the off position he claims there is no draw.  A few days later, although I consistently switched the toggles off, my battery was dead.  It hadn't been replaced after months of external recharges so I replaced it – it was only holding 20% charge.  Within a few days of very cold weather (20's) it was dead again.   I only average 20 miles driving per day, so to ensure my car starts when I go to work and return home each day, I must allow it to idle with lights, heater and accessories off  for about 15 minutes each evening and use my charge box a few hours on weekends.  At this rate I'll need a new battery soon.

I didn't return to my mechanic until last week because he was out of the country for some time.  After testing again, he insists there is no draw when the switches are off.  I learned about parasitic draws online and discussed them with him.  These cars are packed with computers, light & heat sensors, etc.

(QUESTION:  Is the heater supposed to turn itself on when I start the car even though I shut it off every time I park the car?)

My mechanic believes Chrysler knows exactly what is going on but feigns ignorance to avoid liability.  If you can offer no further advice I will next instruct my attorney to contact Chrysler re: this lemon.  Darts to an elephant?

Any more suggestions?


Answer
Hi Patrice,
My inclination would be to ask your son to measure the current draw again when the car is shut down and to leave the meter connected and check it occasionally during a few hour period. And has it indeed been remediated to a lower level subsequent to the toggle switch installation as compared to before that was done? There has to be an unnecessarily high draw down unless the charging circuit is at fault.
I would also turn off the heater/AC control before shutting of the car in the event that it is failing to automatically disconnect its drawdown on the circuit.
Then when you know what the current draw actually is you can relate it to the rate of discharge of the battery and possibly find out if the source of the drawdown is still undiscovered.
I wish I had the circuit diagram for your car but I haven't found a manual at a reasonable price as yet. I'm only able to work with the '94 LH and Haynes 94-7 manuals which is skimpy.
Roland