Everytime I let my car sit for a few days the battery goes dead. I replaced the battery and had the alternator checked. I just got my NSX back and have been driving it for a few days, went outside this morning to start the C4 and it was dead again. I had a 1988 928S4 that did the same thing. Is this normal for the C4's? If not what are the common things to check? It is a 1990. Thanks
Rob Hunt <img border="0" title="" alt="[Frown]" src="frown.gif" />
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If you have got current drain, likely suspects could be the interior, boot & bonnet lights staying on when the doors, boot(trunk) & bonnet are closed. Make sure the switches work properly when everything is closed.
1991 C2 Coupe Zyclam Metallic (L999/82X - match to sample), Ruffled Cashmere Leather, Zyclam coloured dial surround, LWF/RS Clutch, Cup By-Pass, RUF twin tail pipe, KW V3s, H&R sway bars, Carbon Strut Brace & Club Sport Steering Wheel.
By the way, you shouldn't just start and leave the 964 idling to keep the battery charged as this is bad for the engine. Better solution is to either disconnect the battery (or fit a battery cut out switch), get a trickle charger, or better yet spend lots of money but get the current drain solved.
If it helps, I tracked my drain problem to a permanently live powered Radio aerial - it should only become live with the ignition switch in the 1st position yet was powered even when the car was shut down and locked.
I discovered this by taking out each fuse from the fusebox (as recommended in the article mentioned at the website listed above), and testing the draw on the battery using a multimeter.
The culprit was the radio/booster circuit (#38 I think) because when removed, this single-handedly stopped the drain, and pointed me in the right direction as to where to begin looking in more detail.
The other obvious place to look is the door switch, which happended to me and caused the battery to drain down in 3 days.
When my engine is turned off the window and sunroof are still operable as long as the doors remain closed. Once a door is opened power to the above circuits are disconnected.
The best way to check is to find out if the interior lights turn on when you open the door, and if the windows still operate. If the lights are off and windows still work when door opens, then it is time to replace the door switch.
Thats weird what you say about the windows operation. On my car when the ignition is off the windows only open when the doors are open (and so does the sunroof). Doors closed and they don't open anymore.