Alright here's the story. I was fixing the window motor on both doors, successfully did that and when I put it all back together the battery died so I hooked it up to a wall charger. We started it up while it was on the charger by accident and now everything is screwed up. All my gauges are out except the oil pressure and battery meter. My radio went out, and my trunk won't open by the key phob or from inside the car. It just beeps a few times. I checked all the fuses, all are good. Any ideas of what fried, how expensive do you think this will be to fix. My car is a 2000 Z28 convertible, mostly stock.

 

your BCM exploded. 10 bucks at a you-pull-it junkyard. It's actually not a bad idea to have a few lying around.

BCM= Body Control Module

They should all be the same from 98-03, v6 or v8 doesn't matter.

Not too hard to replace either, just a bit of an awkward angle, its behind your glove box closer to the side (rather then middle of car). Pulls right out (it sits in a big plastic clip/frame that needs a little finesse to pull from), or slides right in.


P.S. disco battery before install, check my last reply also

 

I was gonna say the same thing ^^

 

Interesting... Thank you guys so much! At around $10 I'm happy about that. So it's behind the glove box then... I'll do some poking around tomorrow find out exactly where it is. What's the approximate size dimensions for the bcm? Would this be something I can do on my own easily? Will all the gauges still be calibrated correctly, and will my odometer still read the correct mileage, we have driven it about 300 miles since it went out. Sorry for all the questions, glad you guys can help me out. Thanks.

 

i'll take a few pics sometime tonight and put em up, watching a movie right now

but it's about 4x6 inches. black plastic. if i remember correctly, 3 connectors

 

here is a link to a brand new one. don't be discouraged by the price, just pull it from a junkyard. not really a hot item so you should find it in the first 98+ f-body you find (camaro/firebird use the same unit).

http://www.rmsautoparts.com/proddetail.php?prod=9353691.

btw makes it alot easier to get to if you remove the glove box. at the junkyard i ahem "discreetly removed" the glove boxes to get to them. but in your case you'll want to remove it properly, open the glove box and there is a pressure point at the sides i think that will allow you to open the glove box further, exposing the bolts.


ahhh poop, tv just cut out. i'll go take a pic or two.

 

thats with my glove box fully opened up. you'll have to remove the panel behind the glove box as well since the BCM slides out downwards. just jiggle it around till you can slide it out, but trust me it will. probably gonna have to play with it for a while.

 

Why did all the power **** go out because of the bcm? Could you explain that to me plz Grim crow?

 

he blew it when he tried to start the car with the charger still connected. the bcm controls all the things that died in his car.

 

Ah so that actually controls the power to those things? Thanks I suck with electrical so I thought I'd ask!

 

Yeah, either its the BCM itself thats blown or power to the BCM. So I mean its possible for it not to be the BCM, but im pretty sure the BCM is the weak link in that electrical mess.

TECHs feel free to correct me, just working off experience, not really an electrical guru or anything.

 

Not all BCMs are the same. There are at least 2 different ones depending on what options your car has, and there might be a different model for the convertibles as well.

If you pull one from a junkyard, see if you can get the key from the car. At a minimum, make sure you get the VIN of the car you pull it from, and a certificate from the yard stating that the car is wrecked otherwise no GM dealer is going to cut you a key to match. If you can't get the key, or the VIN, you'll end up needing to do the VATS bypass unless you get really lucky.

 

I have a problem that's almost the same.. I have no radio no running lights, break and turn signals work, no guage lights.. Only oil pressure and bat voltage work.. I pop the tail lps as soon as I turn the key.. The pwr accy lasts about 5 sec after .. I was thinkin bcm but everything works untill the fuse pops.. I'm at a loss of what to do..

 

I also just changed the flasher with a tridon el12 and led drl/turn signal

 

getting the key would be cool but doubtful, check this link for a no-key scenario:

http://vats.likeabigdog.com/

at worst you have to try it like 15 times (resistor values) till it works

 

Interesting assumptions made here. The BCM does in fact provide power for the radio and power windows (RAP circuit) and it does control the hatch release as well as power locks. But it is not related to the dash gauges in any way other than some of the idiot lights (seat belts, security). So even if it is bad, it couldn't be the cause of all the problems listed.

There were only two different BCMs used in 98-02 F-bodies - with or without the factory alarm system. When buying a new replacement now, you get the one with the alarm system because it is interchangeable whether you have an alarm or not. If you have an alarm and you get a used one, you should check that the donor car also had an alarm (look for the LED on the top of the dash or RPO code UA6 on the door sticker).

Used BCMs can not be reprogrammed so you will have to work around the VATS problem one way or another - bypass, take VIN number to dealer, blind luck...

The BCM gets its power from two battery sources - the COURTESY fuse in the dash fuse panel and fusible link E under the hood. I would not be at all surprised if the problem is actually the fusible link rather than the BCM itself. But then I'm a firm believer in testing and diagnosing rather than throwing random parts at a problem.

 

whitebird- you do realize that the point of a "help" thread is to help the OP diagnose the problem. If we all responded to the OP with "I think I know what might be wrong, but I'm not gonna help you because you should diagnose it yourself or pay someone to do it right." wouldn't that sort of defeat the purpose of asking for help? We give the person an idea of what might be wrong, and they can diagnose that particular part, or "throw parts at it." It's up to the OP to decide on how to take the advice. Although, even through the snipes you still helped the guy with your opinion about what might be wrong so I guess it's ok if you were a little rude ;-P

btw, whitebird thanx for the monsoon writeups, seriously.. it helped alot.

 

I think you may have taken his post incorrectly.

Whitebird did, in fact, give an idea of what it could be. However, he suggested not to spend money for parts that may or may not fix the issue.

The OP (and others, I'm sure) need to do some minor electrical diagnosis' in order to properly find the problem. Imagine the OP bought the BCM only to find it didn't work. And, in fact, it could've been something cheaper to fix or replace. The OP would have potentially spent unneeded money for something unnecessary at the time. Perhaps it's not a big issue in this scenario, but I can give you one I faced recently that'll make you think otherwise.

I recently got my brother an '04 F-250 Super Duty. It started running like **** a few days after getting it. It lasted very well on the 500 mile trip home. Than, it decided not to start. I don't know much about diesels at all. So, I did my research. Read some schematics, checked every associated fuse, etc. Everything was in working order. Than, I thought that perhaps it could be the FICM. I tested the pins on it and sure enough the readings were far below normal which would cause a no-start.

So, I went to the dealer and grabbed a new one. Roughly $750 or so. Got home, plugged it in, and nothing. Still didn't start. So, I rechecked everything and came back clean again. Confused as hell, I did some forum hopping to find that they need to be programmed.

Got it programmed at the dealer for $125 for a 5 minute job... Started up right after and has ran great since.

Imagine if I didn't check my bases, grabbed the FICM, and it still didn't run. I'd be out of $750. When in reality it could've been anything from a fuse, to a short, or even a loose ground.

It always helps to cover your bases is all that Whitebird is stating. Instead of guessing and checking like you would in middle-school math, take the more intuitive approach and narrow down the issue. While it may be more time consuming, you learn in the process. You become more indepth with your vehicle and how it operates. Seeing a large voltage drop due to excessive resistance over an ignition wire for example could prevent you from purchasing new coils, plug wires, plugs, etc. which wouldn't solve the problem and would only cause more of a headache.

From what I've seen and read, Whitebird is a wise man. He knows his stuff and is always eager to assist. It would be wise to take his advise when he suggests something instead of ignoring it and buying everything under the sun to not fix an issue.

 

Well, that's the first time I've been accused of not offering help. You missed my point. There were assumptions made about a possible cause for the problem that didn't explain all the symptoms. That always raises a red flag for me because it means that either there are multiple problems that started at the same time from different causes (possible but unlikely), or the diagnosis is incorrect and more evaluation is needed.

I never worry about telling someone that a fuse is the likely cause of a problem because it's a 25 cent item that is no big deal if it doesn't end up solving the problem. But I hesitate to recommend someone replace an expensive part without being certain it will fix the problem. I try to analyze the symptoms and post suggestions about which areas to check and how to test. To me that is more helpful in the long run than replacing parts without testing and I won't apologize for that.