Last post on Nov 28, 2013 at 8:28 AM
You are in the Chevrolet Impala
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Chevrolet Impala, Lights, Electrical, Sedan
#75 of 446 Re: CAR WON'T START AFTER TWO DAYS [01impalals]
Aug 08, 2006 (12:22 pm)
I was having the same battery drain on my 2002 impala with 92,000 miles on it. The only thing that was malfuntioning was that my digital radio clock would lose about 15 minutes overnight. As long as I drove the car every day everything was ok, but when I let it set for 2 or 3 days the battery crapped out. After 3 batteries and many hours pulling fuses and doing a current draw test on each circuit I found that the clst/bcm fuse was fluctuating between 500 and 36 miliamps. I was told that the draw on an idle vehicle should be no more than 45 miliamps. As a test I reset the clock, removed the fuse, recorded battery voltage (12.5 volts), and left the car set for 24 hrs. The next day the battery voltage was still 12.5 volts. I replaced the fuse, started the car and to my surprise the clock didn't lose any time. I think the BCM is telling something to work when it shouldn't be working but I'm not going to shell out $300 until I'm sure it's the problem. BE ADVISED THAT THE CAR WONT START WITH THAT FUSE REMOVED, but I'm pulling mine whenever I'm not using the car until I get the problem solved. P.S. The clst/bcm fuse is 10 amps located in the driver side fuse panel. Hope this helps.
#76 of 446 Re: CAR WON'T START AFTER TWO DAYS [kjoshn]
Aug 09, 2006 (10:37 am)
BCM is the body control module. Helps monitor stuff like door position, chimes, etc. It is normal for it to draw perhaps 1/2 amp right after car is turned off, because some modules don't power down immediately. But after about 15 minutes it should be down to say 40 mA. To test this accurately, you need to close all doors, yank the fuse, and without opening anything measure the current. Maybe you already knew that.
#77 of 446 Re: CAR WON'T START AFTER TWO DAYS [bxd]
Aug 09, 2006 (4:44 pm)
The way I understand it is that the BCM controls just about everything electical in the car except maybe the engine and tranny. That's why when a new one is installed they need to know the vin number so every option that is in the car is programed in. Anyway, I did know about the doors needing to be closed. I hooked the meter up and laid it on the seat, closed the door and waited. It took about 5 min. to cycle down to 36 m/A's and another 5 min. to start cycling up and down from 36 to 500 m/A's. It stays on 500 for approx. 15 secs. and 36 for 5 secs. I watched this for about an hour and decided it wasn't going to stop. I just checked the battery volts again after 36 hrs. and it's still 12.5 volts. Put the fuse back in, started the car and the clock is keeping perfect time. So all I need to figure out now is it the BCM, cluster gauge assem. or the radio? Any suggestions anyone? For now I'm going to install a switch on that circuit and call it my anti-theft ignition kill switch.
#78 of 446 Re: CAR WON'T START AFTER TWO DAYS [mrwayne]
Aug 11, 2006 (1:58 pm)
Update on 2001 Impala Still won't start after 2 days.
Alternator is good, I haven't had a problem with the clock
or the radio. I don't really wanna miss with the BCM, but its not ruled out yet.
#79 of 446 Re: CAR WON'T START AFTER TWO DAYS [01impalals]
Aug 11, 2006 (3:37 pm)
Sorry to hear you still have your problem. Believe me, I know the frustation your going through. I don't know if you read post #1897, but that's the position I'm in now. I did put a switch on the clst/bcm circuit and have not had any drain problems since. When the switch is off the power door locks,power trunk, dome lights ignition switch will not work. I hit the power locks when getting out before I turn the switch off and then use the key to get back in. I'm not a cheapskate and I would have a new bcm installed by the dealer in a second if I knew that was the problem. But before I did all of the above I got socked $450.00 for an altenator by a gm dealer who said it was bad. I knew it was charging and I thought they meant it had a shorted diode or something that was leaving the current backflow so I told them yo replace it. When that didn't work I took it back and they said the old alternator was bad and maybe the battery is bad also or I might have another problem. Needless to say I didn't have much faith in this service dept. and said good-bye. The only other thing I can tell you is that disconnecting that circuit doesn't seem to have any ill effects to the car after it's reconnected. It starts fine, runs fine and everything works the way it should, including my clock and no more dead batteries. So that's the way it's going to be for me until I can find the exact cause of this drain. Good Luck to you
#80 of 446 Re: CAR WON'T START AFTER TWO DAYS [kjoshn]
Aug 12, 2006 (9:33 am)
It wouldn't surprise me if it were indeed the BCM. Some of them develop minds of their own, and do thing like flash lights and honk horns. After 6 months of weird electronic
occurrences, I finally had my BCM replaced (and programmed).
Besides the common security light and no-start problem, the power locks wouldn't work, and, if you're familiar with the 10 minutes of accessory power you have after you shut your ignition off, well, after ten minutes, my BCM would shut down fine, and then a few seconds later, it would come on again for a few seconds, then shut down again. It would continue to do this indefinitely. The new BCM solved all the problems I had.
#81 of 446 Re: CAR WON'T START AFTER TWO DAYS [mrwayne]
Aug 12, 2006 (3:56 pm)
Thanks for the feedback mrwayne. The problem you had certainly sounds like mine except everything works fine other than my clock loses time (10 -15 mins. in 12 hrs ) when the car is turned off. I guess every BCM has it's own personality. Well, I'm going to bite the bullet and take it to the dealer and have it checked. Could I ask you the approx. cost of the BCM and programming that you paid? Just so I have an idea when I'm quoted an estimate. Thanks again.
#82 of 446 Re: CAR WON'T START AFTER TWO DAYS [kjoshn]
Aug 13, 2006 (9:03 am)
Labor was $173.11. The BCM is $187.45. With tax and misc. materials, I paid $380.50 (this was three days ago). This included installation, and programming (and a car wash). You can order the part directly from gmpartsdirect.com for around $97 plus $21 shipping. (The price of the BCM keeps creeping up. Last year it was as low as $84.) If you buy the BCM yourself, then there's the issue of getting it programmed according to your VIN. (So that all of your options can be programmed in). This is an issue that I've never been given a definite answer on. Some will say everything works without programming, others, especially dealers, say it must be programmed. I'd say the safest thing to is go to the dealer and have it done right, and get whatever warranties go along with that, although I can understand many people want to get around spending that kind of money (especially if they don't really have it). Be aware that some dealers try to charge much more. Some people have paid $500-$900 for this same service. The prices I paid were exactly in line with what GM says it costs (including labor time), which is about $360
plus whatever your state tax is, plus whatever small shop and/or material fee there is.
#83 of 446 Dashboard Lights
Aug 13, 2006 (10:00 am)
Earlier in the summer, I had a similar no-start problem as many folks on here have/had. Pulling and replacing the BCM fuse did the trick to start the car, but now I'm plagued with a few odd problems:
First, my turn signals had previously malfunctioned from time to time, but could be "fixed" by activating the hazards. Now when they malfunction, it's pretty bad and there's usually nothing that can be done.
Second, when the car reads that it is dark outside (and the dash lights activate in a different mode), the dashlights are very very faint. At night, I cannot read my speedometer, tachometer or fuel gauge. This is ONLY at dark, though. The radio and other instrument panel related lights are also very faint.
Finally, I'm encountering some difficulties with my power windows, but only on the driver's side. I can no longer press the button all the way down to roll my window up, but rather must keep it in a certain "sweet spot", which means being held about 3/4 of the way down.
I'm trying to sell this car soon, and these little inconveniences are not going to help the matter.
#84 of 446 Re: Dashboard Lights [jtactile]
Aug 13, 2006 (7:12 pm)
I can't address the turn signal problem, but have some thoughts on the other two.
The power window switch is a fairly common problem...same thing happened to me about three years ago on my 2000 Impala. I managed with the "sweet spot" approach for probably six months or so, and then finally one day the switch quit entirely (or course, with the window down). The problem is in the switch, and is easily replaced...but as I recall the part is $90.
On the dash lights, you don't mention trying to adjust the intensity of the dash lights by turning the light switch on the dash - I'm sure you have, but if not it's possible it could be turned down, which would only impact things at night.