Alright I haven't really been able to find a definitive answer to this. I have read over the stickies and did some searching. From what I gather, most of the BCM issues result in malfunctioning radio and windows.

Well here's what I have going on.

When I bought my car it came with no radio and no key FOB. Not a big deal to me. I plugged in the radio from my beater and it works like a charm so no issue there. My window motors also work but are slow which I know the reason for that is the common motor issue.

However, my power door locks do not work at all, my trunk release does not work, and probably two times my car alarm randomly went off when I opened my door with the key. Also, the little interior lights by the door handles and in the ashtray do not work.

Finally, I know it is not related to the BCM but my body harness does not have a plug for the second cigarette lighter outlet right next to the cup holder, there is a plug but it is not the same style connector as in the back of the outlet.

So any help would be appreciated. I figure if it is the BCM I will either try and get a new BCM or find someone selling a used BCM with keys and FOB together so I don't have to worry about bypassing the VATS.

 

It does seem like the BCM might be the common item in some of your issues but there are other possibilities that you should check first because replacing a BCM is either expensive or a hassle or both (depending on whether you buy a new or used one).

The door locks are controlled by the BCM but the first thing to check is the COURTESY fuse (20 amp #8) because it protects that circuit.

The hatch release is also controlled by the BCM but also uses the COURTESY fuse on the control side of the relay and the PWR ACCY (15 amp #7) fuse on the actuator side.

Having the alarm activate when you use the key to open the door is normal operation if you take more than eight seconds to get in and turn the key in the ignition. The alarm is only disarmed by the remote fob or the ignition switch - not by the key in the door.

The interior lights in the door and ashtray are not connected to the BCM in any way. They are #74 bulbs which have likely burned out. They are very difficult to replace because they tend to shatter when you try to pull them out of their sockets.

This is what the power outlet plug should look like:

Pin A is an orange power wire, pin C is a black ground wire, and pin B is not used. If your harness connector looks like this but doesn't fit your power outlet, perhaps a previous owner replaced the outlet with a generic one from a parts store. The generic ones usually have a round center power pin and a flat "quick disconnect" ground connector on the outer barrel.

 

Sounds good I will check this all out tonight. I appreciate it. I am pretty sure the fuses are all good but I will check again.

I did not know that about the alarm system that's good to know.

The power outlet you described as the generic one sounds like what it is IIRC. I will look also.

However I replaced the door bulbs and ashtray bulbs with LED lights since I figured the old ones were burnt out. I tried the LEDs in both orientations to make sure I had the polarity correct also and they still did not work.

 

Never rely on visual inspection of fuses (especially in older cars) - they can look fine even when they are blown. Always use a tester or replace with a known good fuse.

If you have a generic power outlet you have two choices... you can buy a GM replacement (part #10202970, about $11 at a dealer, $6.50 online) or you can connect the generic one by cutting off the harness connector and connecting the orange wire to the center terminal and the black wire to the outer barrel connector. That $11 price kind of makes you wonder why the previous owner would cheap out on a generic one.

If all the other instrument panel lights are working (HVAC, gauge cluster, etc.) then you can assume that the headlight switch, dimmer switch, and fuses are all okay. So either you have a break in the wires someplace or there is a problem with the bulbs. If you have a test light or multimeter, you can check for power at the bulb sockets to see if it's a wiring or bulb problem.

 

Ok just checked both fuses and they are good. When I hit the door lock button I can hear the BCM click but nothing happens. I assume that means it's bad?

Also the trunk release button still doesn't work but that doesn't make the BCM click when I hit the button. So is the wiring most likely bad then?

Same with the lights. Pulled the courtesy fuse and all my dome lights and such went out. Plugged it back in and still nothing. Wiring again I assume. So when I pull the door panels off to replace the passenger motor and check the tracks on both sides I guess I'll have to look.

 

Since you hear a click when you try the door lock switches, it's probably safe to assume that the switches themselves and the wiring between the switches and the BCM are also okay. But the clicking noise also indicates that the BCM is probably not the cause of the problem. I would suspect a problem with the gray wire between the BCM and the two door lock actuators. It is unlikely that the tan (left) or gray/black (right) wires are the problem because then only one side would stop working.

There are numerous points of failure for the hatch release. You'll really have to use a test light or multimeter to do some diagnostics. Two common issues are the release actuator itself or the coil ground for the release relay (which goes to the parking brake switch on your car).

The door lights and ashtray light aren't part of the courtesy light circuit - they're part of the instrument panel illumination circuit.

 

So would I need to pull the BCM out enough to access the wires but not unplug it? Or would it be on the door lock end?

Hmm as far as the parking brake switch connection. Where is that exactly? I know my "BRAKE" light is on due to my ABS delete and it was on before. But I would think that would mean it thinks the parking brake is on all the time. Is the actuator right next to the release mechanism or is it hidden in some ridiculous area and connected with a cable? Wouldn't surprise me if it was the second thing.

The rest of my instrument panel works and lights up fine so would that indicate an issue in the wiring? Oh my steering wheel button lights don't work either.

 

For testing purposes, it will be much easier to test at the door. Pull off the door trim panel and locate the two wires going to the door lock actuator (gray and tan for the left door, gray and gray/black for the right door). Test for power on the gray wire and ground on the other wire when you press LOCK. Pressing UNLOCK causes the reverse - ground on the gray wire and power on the other wire.

If you get the proper power and ground in those tests then you need to replace the door lock actuators. If you don't then you need to start checking the wires for breaks. First run the same tests at or near the BCM - that will confirm that the BCM is in fact sending the right signals. If not, replace the BCM. If it checks out then start the tedious process of tracing the wires looking for breaks.

The parking brake switch is mounted to the parking brake handle bracket under the console. It's a simple grounding switch so it has only one wire going in and it grounds through its mounting point.

There is a separate 1-amp fuse for the steering wheel control illumination - fuse #13 labeled STG WHL CNTRL. Check that first.

 

There should be three connectors back there. One for the lighter, one for the power port, and one for the TCS/Convertable switches. If you don't have TCS or a drop top, that connector will just site there unplugged.

The lighter and power port connectors look almost identical but differ in the square key. (at the intersection of the outer body between pins B and C in the picture above) The lighter has the key on one side and the power port has it on the other.

 

Ok sounds good. Once I get my car's brake situation figured out I will pull the door panels off and see what the deal is with that.

As far as the steering wheel control not sure I remember seeing that fuse. Where on the inside block should it be?

I do not have TCS but it is a convertible. I have an empty plug on the harness but it does not fit the socket for the power port

 

What happens if you lock the door manually, then hit the button to unlock? Same thing, or does it actually unlock?

I had a problem on my 98 with the relays in the BCM for my doors. Lock wouldn't always lock, the relay would click but that was it. Unlocked worked OK. I ended up buying a random half-broken BCM from someone here and swapped out the relays (could probably find the actual replacements if I looked hard enough, I just took the easy way out).

 

Can you post a pic?

 

I'm pretty sure it does the exact same thing. I will try it out tonight to be sure.

Yea I will grab a picture tonight

 

WhiteBird00: Ok so tested the actuator wiring. When I put the power lead on the tan wire and ground on the grey and hit lock I get power. Good. However when I put the power lead on the grey wire and hit the unlock button I get nothing but when I hit lock I get power again. Didn't get a chance to check the parking brake switch. I did check the steering wheel fuse and it looked good. However I completely forgot to actually test it.

SparkyJJO: Doing the manual thing you said doesn't make a difference. I have a buddy that is going to pull the bcm out of his roller and I'm going to try that anyways just for *****.

wssix99: I rand out of bandwidth on my photobucket for the month so here is the links to the empty plugs I have under my center console. The lower power plug is actually plugged in and the cigarette lighter is not. I found this other small plug under there too.

http://i855.photobucket.com/albums/a...ps928ffd18.jpg

http://i855.photobucket.com/albums/a...ps42672820.jpg

 

You should have power on gray and ground on tan when pressing LOCK. They will be reversed when you press UNLOCK - power on tan and ground on gray. Sounds like lock is working (even though you reversed the testing) but UNLOCK is not producing the correct results.

The reversing polarity nature of this circuit means you can't test with a test light inline in the circuit - you have to use a multimeter to test for direction of flow rather than just presence of power (a test light will light up regardless of current flow direction). You can use a test light by attaching the clip to a good ground such as the stud behind the left kick panel and then testing individual wires for power with the probe end.

 

I did the second thing you mentioned with the stone age multi meter we have. I left my new one at my apt. I grounded it on the door and it showed power on both wires for lock and nothing on unlock. What would that mean since the lock works. When I press lock or unlock with it plugged in the lights do dim and the BCM clicks so would that mean both are drawing power and working but the actuator is bad? I only tested the drivers side though.