Hello all,
I've searched and searched this forum for any similar problems to no avail; my issue is with 2007 DTS level I or II. Recently, the dic displayed a battery saver msg. and the air conditioning shut off. From there, display started indicating service messages for stabilitrac, ABS, charging system and I believe one other issue, which escapes me at the moment. Representative warning lights illuminated. While heading home I checked battery voltage on the dic, which showed between 10&11 volts,considerably below its normal of 14.2v. Upon arriving home, I tried restarting the car, nuthin'. No lights, radio, zilch. Attached a battery charger and the car started right up. Disconnected the charger and with my trusty voltmeter measured 12.8 volts at the battery under hood terminals. The car would restart fine and all systems normal, but the info display showed battery voltage less than optimal. This occurred several times over the next few days, so I tried researching the problem. I fully charged the battery and had it load tested, checked good. All under hood fuses were good. I tapped on all the relays including under rear seat. The problem vanished only to return a short time later. My research has led me to think a grounding problem is at fault, but I don't know where to check. I thought it could also be a faulty battery current sensor. Since this was an inexpensive part I replaced it. No joy I drove the car around a bit to see what the voltages were on the display and it fluxed between 10&12.5 volts. Came home and wondered. This Morning car wouldn't start. Attached the charger to start car and disconnected it after starting and shut the car off. Disconnected battery cables and measured battery voltage with meter, reads 12.8vlts. Left the cables disconnected and came inside to beat my head against the wall.
Any help from a capable spark trician tremendously appreciated.

 

While awaiting a response, I decided to re-position the new battery current sensor and tape it a bit better to the negative battery cable to insure better contact. I road tested the vehicle and while the voltages on the DIC appeared more normalized, things still went haywire when a load was applied, ie., the air conditioning was turned on. Battery saver mode was not entered but display indicated: service traction control, service stabilitrac, service ABS. I appreciate you all who took the time to review my electrical issues, but no replies lead me to believe this will have to be a case for the dealer to resolve, unfortunately. Ka-ching! Tiime to rob the piggy bank.

 

Sounds like a bad alternator. Check the voltage at the battery with your multimeter. First, before you start it and again with the engine running.