Questions and Answers

Dodge Caravan Dims Out Q. Hi I recently purchased a 1999 Dodge Caravan SE, 3.3 liter engine, automatic transmission, 65,000 kilometer's, with ABS, P/S and cruise. It seems to have a rather annoying problem. When the car is idling the alternator does not seem to put out enough power to keep up with the accessories.

This is my most common example: I live in Manitoba, Canada and it gets very cold here (-30° Celsius) so running the heater fan on high and having the rear defrost on is mandatory. I have these two accessories on along with the headlights on the headlights will almost dim by half at idle, and the output of the heater fan will reduce as well, and then pick up again when the engine spins at about 1000rpm.

When I first notice this I was within my 30-day fix-it warranty so the dealer did a load test and replaced the belt and alternator. I left the dealership and turned right back around since the problem was still there, they did another load test and everything seemed fine (although I got a feeling they were trying to get rid of me).

I checked the belt tensioner and it seemed to be okay, the battery is on the small side for the climate I live in but shouldn't impact this. We've had no other problems with the van and really enjoy it but I was wondering if this condition was normal. My old car (1989 Chevy Cavalier, 2.0 liter engine) did not have a similar problem if I'd flick the defrost on the lights would dim a little (almost not noticeable) but then pick up again. Is this common of newer cars (this is my first newer car)?

I noticed during the first load test there was 13 volts to the test machine but when I turned all the accessories on it drooped to 10.5 or so during the second load test there was maybe 14 volts but dropped to high 12's this is without load from the machine itself.

Any ideas? My first guess was the alternator was bad, belt slipping, or a bad tensioner these all seem fine. My old 1965 Plymouth Barracuda had problems with its voltage regulator but I wouldn't know where to start to look for it on the Caravan. Someone told me it was in the BCM (Body Control Module) but that's like $800.00 US to fix. Any ideas?

Dominique

A. I don't believe there is anything wrong with your alternator or voltage regulator. I think it's a battery going bad. 10.5 volts on a load test is borderline bad. And in your climate, that is not very good.

I would suggest replacing the battery with the proper one and this problem should clear right up. When you replace it, I would recommend getting a larger (electrically, not physically) battery. They are only a few bucks more, but the extra capacity is well worth it.

By the way, the voltage regulator is built into the alternator.