Wierd electrical problems

Well I just got home from school today and drove my car. My alarm has been going alittle crazy so I disconnected the sensor in the trunk and it has seemed to solve that problem. Now sometimes my interior lights stay on and start to fade in and out. Also I noticed that everyone once in a while my "mileage trip" thing near the odometer will reset. Nothing happens to the radio so its not a power surge through the whole car. I'm really perplexed by these problems...any suggestions?



Mark

Ok now things are getting even wierder. Yesterday my alarm went off for no reason and i've had the shock sensor disconnected for awhile now b/c it used to go off a few minutes after I armed the alarm. My horn sounds different when I lock the car (It doesn't sound as loud and it only beeps 1 time). The courtesy lights stay on for like 5 minutes after I get lock the car. It seems as though my alarm is very screwed up, I don't even really want to drive the car to far b/c I don't know what its going to do next. Help :confused:




Mark

Its the factory alarm

Go get you battery checked, I bet you need a new battery. My trip odometer used to reset, and some of the lights used to act funny, and I put a new battery in and it solved all the problems.

Now even wierder things are happening. I went to NAPA today to pick up some seafoam and as soon as I turned into the car parking light my ABS INOP light went on along with my BRAKE light. Then the car just died and wouldn't start. Nothing worked electrically, no lights, no keyless entry..nothing. I went in NAPA and the guy came out and check all the fuses and tested the battery and said it was fine. He tightened the battery and the car started up again...ok I thought it was a loose battery. Then I locked the car with the keyless entry and went in to buy seafoam. When I came out it did the same thing and wouldn't start to I disconnected the battery and it worked again. I drove it home, armed the alarm and it worked fine...nothing seems to be wrong now. Can my Body Control Module (BCM) be going bad, is that why my alarm is messing up sometimes?

I would suspect that your ABS and brake lamps were caused by a low voltage condition. Undercharged battery or loose connection somewhere. You should be getting 13v or more from your alternator when the engine is running. Use a meter to look at it if you need to. Check all power connections on the RH shock tower.

It is also possible that your BCM is causing an intermittent drain on the system. You said in an email to me that the BCM did not diagnose when you tried it. Did it give you any confirming chimes at any time? That diagnostic procedure is from a 1996 manual and I assume the 1997 would be the same.

It chimed twice just didn't flash any SECURITY lights. I got the battery tested at NAPA and it was fine, I also tightened all the connections. If the BCM is causing a drain is there any way to fix that or is it a bad BCM? The car seems to be running fine now, no problems. I'm going to give it a few days and see if anything comes back. I'm confused on why my courtesy lights would dim in and out while driving and why they used to stay on for like 5 minutes after I locked the car (this is why I suspected the BCM and not just a battery problem although it seems that I may have had a loose connection).

You might try the diagnostic procedure again and be sure to follow it exactly. Confirm that it passes each step by the chimes. You should get 3 chimes when it is in diagnostic mode.

The BCM could very well be bad, but the manual says they are pretty reliable and that wiring or circuit problems are more likely. You might want to confirm that the plugs and wiring at the BCM are good.

If you need to buy GM parts, I recommend either of these guys (gmpartsdirect frequently robs you on shipping):

Dal Slabaugh: 877-448-5451
email: lockitup@bright.net
VanDevere Buick/Pontiac/Olds (http://vandevere.com/) Akron, OH

Jason Cromer: 877-726-8295 or 850-243-8826 (direct parts dept)
email: gmparts@samtaylor.com
Sam Taylor Buick/Cadillac (http://samtaylor.com/html/parts.html) Ft. Walton Beach, FL

I checked the battery and it was screwed down wrong so after I tightened that up and made sure the battery connections were tight i've had no problem with the car dying. Now when I arm the alarm it only beeps once and before it was beeping twice. Also the courtesy lights stay on while driving and after I shut off the car for about 5 minutes (they do this whether I arm the alarm or not). I tried to do that diagnosic again with the BCM and it only chirped twice on the final step and didn't show any codes.

Originally posted by Marky82
I checked the battery and it was screwed down wrong so after I tightened that up and made sure the battery connections were tight i've had no problem with the car dying. Now when I arm the alarm it only beeps once and before it was beeping twice. Also the courtesy lights stay on while driving and after I shut off the car for about 5 minutes (they do this whether I arm the alarm or not). I tried to do that diagnosic again with the BCM and it only chirped twice on the final step and didn't show any codes.

You might check your owner's manual about the different modes you can program into the BCM. I am not too familiar with it, other than what I have read. I have a 1995 that does not have all that stuff. :)

Originally posted by shoebox
You might check your owner's manual about the different modes you can program into the BCM. I am not too familiar with it, other than what I have read. I have a 1995 that does not have all that stuff. :)



Could be why my courtesy lights stay on for 5 minutes???? I didn't think about checking the manual for that since I thought if the car kept doing it the battery would soon start to die. I'll go check now though

Originally posted by Marky82
Could be why my courtesy lights stay on for 5 minutes???? I didn't think about checking the manual for that since I thought if the car kept doing it the battery would soon start to die. I'll go check now though

Not sure what all the features of the modes are without reading up on it. :) Might be normal or might not.

Originally posted by shoebox
Not sure what all the features of the modes are without reading up on it. :) Might be normal or might not.


Nope not normal...just checked it now. The lights are supposed to stay on for 25 seconds after getting in the car and 5 seconds after leaving the car. After reprograming all my features I have a question about the BCM diagnosis.

this is what I did:
went to run
then to off
then removed radio fuse
went to acc (2 chimes)
then turned to off and back to acc within 5 seconds (still on 2 chimes)

Did I do anything wrong?

I DID IT!!! I saw this instructions and realized that I was turning the key fast enough
Turn the ignition switch to the RUN position
Turn the ignition switch to the OFF position
Remove the Radio fuse 17 from the I/P fuse block
Turn the ignition switch to the ACCY position (the BCM sounds 1 or 2 audible warning tones)
Within five seconds, turn the ignition switch to the OFF position and immediately (within 1 second) back to the ACCY position (the BCM sounds three audible warning tones to signal entry into the diagnostic mode)

These are the codes that i got and in the order I recieved them:
21
25
31
35
55
24
32
12
(after this they went to 25 and started repeating themselves)

Another interesting thing that happened was that as soons as I entered the BCM diagnosis mode the courtesy lights shut off ( they've been staying on during everything else I do) what does this mean?

Originally posted by Marky82
I DID IT!!! I saw this instructions and realized that I was turning the key fast enough
Turn the ignition switch to the RUN position
Turn the ignition switch to the OFF position
Remove the Radio fuse 17 from the I/P fuse block
Turn the ignition switch to the ACCY position (the BCM sounds 1 or 2 audible warning tones)
Within five seconds, turn the ignition switch to the OFF position and immediately (within 1 second) back to the ACCY position (the BCM sounds three audible warning tones to signal entry into the diagnostic mode)

These are the codes that i got and in the order I recieved them:
21
25
31
35
55
24
32
12
(after this they went to 25 and started repeating themselves)

Another interesting thing that happened was that as soons as I entered the BCM diagnosis mode the courtesy lights shut off ( they've been staying on during everything else I do) what does this mean?

I read a little more on the codes. Without going into serious detail, it looks like 21 should be the one you should check out first.

I will try to go through part of the diagnostic tree for it:

The first thing is to make sure the courtesy fuse is good. I bet it is, since the lights work.
If the fuse is ok, unplug BCM connector "C2" (black). Connect a test light between terminal "B" and ground. If no light, there is an open on that circuit.

If the test light is on, remove and connect test light between "B" and "E" on connector C2. If the light is on, there is a short to ground on the "E" circuit's wiring.
If the test light is off, replace the BCM.

The codes starting with a "3" are history codes.
25 means that the BCM is seeing the alarm LED ok (good, since you have an alarm).
55 indicates the next two codes are the BCM hardware and software codes (the following 24 and 32)
12 indicates the diagnostic readout will start again.

Shoebox thanks so much, you've been a real help! I have these 2 huge tech manuals in my house that the guy gave me when I bought the car, I never had any idea on how to use them though. I went through it tonight and found exactly what you wrote down. I'm still alittle confused on what is an "open" circuit? Does open mean a fuse is blown? Thanks for typing everything out for me b/c that tech book is complicated. I'm pretty new to this kind of stuff and have absolutey no training. knowing what colors the clips are will help alot. Also can I get a test light at pepboys or sears? I'm gonna do this tommorow morning and i'll post the results.

Originally posted by Marky82
Shoebox thanks so much, you've been a real help! I have these 2 huge tech manuals in my house that the guy gave me when I bought the car, I never had any idea on how to use them though. I went through it tonight and found exactly what you wrote down. I'm still alittle confused on what is an "open" circuit? Does open mean a fuse is blown? Thanks for typing everything out for me b/c that tech book is complicated. I'm pretty new to this kind of stuff and have absolutey no training. knowing what colors the clips are will help alot. Also can I get a test light at pepboys or sears? I'm gonna do this tommorow morning and i'll post the results.

Yeah, you can get a little test light just about anywhere. Now that I know you have the books (great way to learn stuff!), I can just point you in the right direction. Wiring diagrams are on the page following the diagnostic procedure for DTC 21/31 if you are in the 8D-11 section. My book is a 1996, but I think most essential info is the same.

An open is lack of continuity-like the wire is not connected or is broken (ex. power not getting from one end to the other). A short to ground (in this case) is when a wire is touching to the metal framework of the car.

Originally posted by shoebox
An open is lack of continuity-like the wire is not connected or is broken (ex. power not getting from one end to the other). A short to ground (in this case) is when a wire is touching to the metal framework of the car.

So if I find that I have a short to ground then I have to retrace the entire wire and see if any of the copper is touching metal (that will be a pain in the @$$)?

Originally posted by Marky82
So if I find that I have a short to ground then I have to retrace the entire wire and see if any of the copper is touching metal (that will be a pain in the @$$)?

When you see all the lights on that circuit in the diagram, you will really flip. :eek: There are ways to make it a little easier to narrow down. You could even have a bulb that the base of the socket is causing a short.

Originally posted by shoebox
When you see all the lights on that circuit in the diagram, you will really flip. :eek: There are ways to make it a little easier to narrow down. You could even have a bulb that the base of the socket is causing a short.

So if its a short to ground then i'm gonna have to check the wire connection at the BCM then if it isn't that I will have to check every connection to all the interior lights?? How would I do that with the map lights...would I have to disconnect the mirror?

Ok i'm alittle confused by the tech book now. I connected a test light between connecter C2 (black clip) terminal B and ground. The light was on. I moved to step 5 but what does I/P compartment and console compartment closed mean? I tried connecting E and B and the light went on but I don't know if that is because I/P is open (since I don't know what that is)? And if I do have a short on circuit 149 does that just mean I have to retrace all the courtesy lights?


(shoebox i sent you the same message in an email since I didn't know which you'd check first)

Originally posted by Marky82
Ok i'm alittle confused by the tech book now. I connected a test light between connecter C2 (black clip) terminal B and ground. The light was on. I moved to step 5 but what does I/P compartment and console compartment closed mean? I tried connecting E and B and the light went on but I don't know if that is because I/P is open (since I don't know what that is)? And if I do have a short on circuit 149 does that just mean I have to retrace all the courtesy lights?


(shoebox i sent you the same message in an email since I didn't know which you'd check first)

I/P= instrument panel
I/P compartment=glove box :)
console compartment= console :D

Apparently the 97 manual is written in a slightly different way than my 1996 one. What that is telling you is to test with those doors closed and of course, no switches on for the map lights.

Try removing the bulbs as you go and recheck your "B" to "E" test.

I did not get your email, but I am subscribed to this thread and get notification. I don't come to the V6 forum much. ;)

BINGO!!! Turned out that my trunk light was grounded. It seems to work perfectly now! The alarm seems to be working better too. Do you think that the loose battery connections and/or short to ground wire could have been making the alarm act alittle wierd?

Originally posted by Marky82
BINGO!!! Turned out that my trunk light was grounded. It seems to work perfectly now! The alarm seems to be working better too. Do you think that the loose battery connections and/or short to ground wire could have been making the alarm act alittle wierd?

Low voltage can do wierd things so that could have been a cause. Keep an eye on things and see.