kapedogg

iTrader: (5)

Anyone know how to wire up relays to bypass the BCM to lock the doors? The unlock feature works fine since the viper 791xv was installed, but neither the remote or the manual button inside the car will lock the door. The signal goes to BCM, it clicks, but nothing more.

WhiteBird00

iTrader: (4)

You don't want to bypass the BCM - you need to track down the cause of the problem. Start by disconnecting the door lock wires of the alarm system and see if the stock door lock function works. I can post the door lock system schematics if you need them - just let me know.

kapedogg

iTrader: (5)

I could definitely use the schematics and some advice on how to actually troubleshoot that. I had a shop do the install, and I don't know a whole lot about this stuff. I've done a lot of stereo installs, but not alarms.

WhiteBird00

iTrader: (4)

Here you go: door lock schematic. I posted as a link because the image is quite large (2400x1680) although the file is less than 64K.

You will need the wiring diagram for your alarm to figure out which wires control the door lock functions. If you have experience with stereo systems then you shouldn't have too much trouble. Alarms aren't really that much different - it's just a case of making sure you connect the right wires together.

I'm curious though...if this problem started when you had a shop install the alarm why didn't you take it back and have them fix it?

kapedogg

iTrader: (5)

They worked on it for about 7 days and finally gave up, and said they couldn't figure it out. I've been looking for some good guidance or another shop or person that could figure it out ever since. They left it wired up properly according to all the diagrams they had, but the signal seems to never leave the BCM, and I heard of someone bypassing there BCM with relays because of this, but I don't know how to do that exactly. I thought about swapping BCM's, but that's kinda pricey to just try something

WhiteBird00

iTrader: (4)

The first thing to check is whether the BCM is working. Using a test light or multimeter, check that you get a 12V+ pulse on the gray wire in the green 6-pin connector at the BCM when you press the lock button. If so then start looking for where they cut that wire between the BCM and the door lock motors.

If not then check that the red with black wire in the same connector goes to ground when you press the lock button. If not then you have a problem with the lock signal to the BCM. For example, they may have connected the wrong wire from the alarm to the lock signal wire. There are two wires for lock control on most alarms (or else one wire that's switchable) - one provides a positive signal and the other a ground signal. You only use one or the other (not both) but you have to make sure you use the right one. In this case you need to use the ground signal wire (or set the switch to provide a ground signal on the single wire).

If you find you have a proper input signal on the red with black wire but no output on the gray wire then it is likely the BCM itself causing the problem.

kapedogg

iTrader: (5)

Thanks man, I really appreciate the help. I'm going to try to tear into it this weekend!

kapedogg

iTrader: (5)

I finally tore into this myself. There is a signal on the gray wire when I push the lock switch, but the red/black wire does not light up. Now what do I need to do?

WhiteBird00

iTrader: (4)

Bear in mind that the red/black wire grounds through the door lock switches. If you're using a test light then you will have to connect the clip to a power source (e.g. fuse panel) and use the probe to test the red/black wire. With that setup you should see the test light go on when either side door lock switch is pressed. Be sure to try both switches because it's unlikely that both would be bad at the same time.

From the sounds of what you've tested it seems like they must have cut the gray wire someplace between the BCM and the door lock motors. The BCM sends a positive pulse on the gray wire to the door lock motors to lock both doors. If you're getting a power pulse on the gray wire but the doors aren't locking then the wire must be cut someplace preventing the pulse from reaching the lock motors.

kapedogg

iTrader: (5)

Can you tell me where the motors are, so I can trace this wire? All I can see right now is where the gray wire comes out of the BCM and heads into the wall(about 5 inches of wire)
Are there two motors, one for each door lock? Are they the same motor that unlocks them?

I'll check the red/black wire in the fashion you mentioned and post the results.

Hopefully I'm gettin close to figuring this out. Thanks again for all your help.

2MuchRiceMakesMeSick

If you take the door pannel off you will see the actuator.
There is only one actuator per door and it moves the guide/brace that unlocks/and locks the door depending on the polarity in most motors.

WhiteBird00

iTrader: (4)

The motors are in the doors - one on each side. They are the same motors used to unlock the doors. The motor runs in opposite directions depending on polarity so just reversing the power and ground signals changes between locking and unlocking.

The gray wire goes from the BCM through the cross-car harness in the dash to the driver's side near where the left power mirror wires branch off. At that point the wire splits into two - one for each door. The driver's side goes through the rubber bellows near the door hinge to the motor while the passenger's side goes back across the car to the right door lock motor. Since neither side is working you should only have to trace up to the split. I expect you will find the cut someplace close to the alarm module since the problem started when it was installed.

kapedogg

iTrader: (5)

Thanks again for all your help. I'll try to track it down after work tonight, and keep you posted. If I can't find the cut, is it possible to run my own wiring to the motors to double check the issue and possibly fix the problem? What would be the best way to do that?

It isn't a polarity issue since wiring it back to stock didn't work either, right?

kapedogg

iTrader: (5)

I found a gray wire that split off near the power mirror wire split that was inside the drivers side door. It was two gray wires from inside the door running to one that went to the door locks. These were wired up to the UNlock harness with a tan wire, which work.

The driver side Lock harness has a black wire and a gray w/black striped wire.
The passenger side Lock harness has a Black wire and a Black w/white striped wire.
None of these activated the test light when the switch was pressed. I assume since the black wire is the common wire, it is the one with the problem, not the striped wires. So, it seems that the gray wire somewhere along the line gets changed into a different color(black). When you say that the gray wire runs across the car through the dash, is the large wire loom that runs at the top of the dash above the air bag and across? I have no idea how to get to it

I did find a white, 2-pin, female harness on the driver side where the bulk of the wiring is that is not plugged into anything. It has a gray wire, and a black w/white striped wire. They split off from a group of 4 wires total including themselves along with a light blue and orange wire. They then run into a large group of wires including a red and black twisted wire and a white and brown twisted wire. They are plugged into a black block, which then runs a set of wires down to the floor and towards the back of the car.

Instead of trying to trouble shoot all this wiring, could I simply run my own wires from the gray wire at the BCM to the black wires in the harness?

WhiteBird00

iTrader: (4)

I wouldn't recommend running your own wire to the black wire because it's not supposed to be there. The driver's side door lock has two wires - gray and tan. The passenger's side door lock also has two wires - gray and gray with black. Neither side should have a black wire. Both wires can be either positive or negative depending on whether you're locking or unlocking the doors (they reverse polarity to reverse the lock motor). The gray wires on both doors go to positive when locking the doors. The tan or gray with black wire (depending on which door) go positive when unlocking the doors. The reason they are separate is to support the progressive door unlock where the driver's door unlocks on the first press of the remote button and the passenger's side unlocks on the second press. If you replace with your own wire you will probably lose the locking capability of the alarm remote (since you would be taking it out of the circuit).

It sounds like the alarm installer ran a black wire from the alarm to the lock side of the door locks but disconnected the original gray wire. This is necessary on some cars but incorrect for f-bodies. The alarm's lock wire should be tapped into the original wire rather than replacing it. Also, our cars require diodes to isolate the two door locks from backfeed current (not important if you do the progressive lock mod).

Your best bet would be to get the alarm installation manual out and double check that the door lock wire has been connected as specified. You'll have to track the appropriate wire from the alarm brain to each door lock. This is really something that the installer should have done but many installers are better at installing than troubleshooting.

kapedogg

iTrader: (5)

Here's what I get when testing the harness plugged into the solenoid with the clip on a ground and the probe to the harness connections, all of which seems correct

Driver Side Gray wire lock button lights up
Driver side gray wire unlock button, no light

Driver Side Tan Wire Lock button, no light
Driver side tan wire unlock button lights up

Passenger side Gray wire - same as driver side

Passenger side gray/black wire - same as driver side tan

I did have the progressive door lock mod done before this install, which they commented on and used that as their excuse for not being able to get it to work. Perhaps I need diodes or don't, but I don't see any anywhere, could this be it. what type of diode and where do I wire it to give it a try. I'd probably try walking on my hands across Texas if that will get these damn things to work!

I did however find out that occasionaly under certain circumstances the factory alarm will go off, (just lights flashing), i'm not sure why/when, but something to do with unplugging these harnesses and the doors being open while hitting the lock and unlock button, as though it is passively arming itself.

WhiteBird00

iTrader: (4)

Okay, that's good. Those are the correct results with the test light so we know that the wires aren't cut or broken. But that just makes it more confusing as to why the doors don't lock. Unless the solenoids are dead, the current coming through the gray wire should be activating the solenoid to lock the doors.

(I'm going to refer to only the driver's side wires from now on - the same things would apply on the passenger's side.)

It is possible that the BCM isn't providing the necessary ground when locking (i.e. putting power on the gray wire but no ground on the tan wire). You could test this by hooking the test light ground clip to the tan wire (you'll probably have to strip a small section) and then testing for power on the gray wire when the lock button is pressed. If this works you'll know that you have a complete circuit and the solenoids might be the problem.

However, at this point I would take a different path because I suspect that something in the alarm hookup is either preventing the ground or reducing the current to the solenoids. Since we seem to be back to the alarm system causing the problem I would recommend finding and disconnecting the alarm's door lock/unlock wires to test if the locks return to their proper factory function (with door switches and factory remote). These wires will probably be connected to the gray and tan wires someplace close to the BCM.

kapedogg

iTrader: (5)

I think at one point in time I had wired it back up as stock wiring, and it didn't work. I will go home at lunch and try checking the tan and gray wire as a circuit.

I can't imagine that both solenoids would go bad, but who knows, maybe they sent a signal through the gray wire that fried them both simultaneously, but who knows

kapedogg

iTrader: (5)

ground clamp on tan, probe on gray pressing Lock = nothing
ground clamp on tan, probe on gray pressing UNLock = lights up

ground clamp on gray, probe on tan pressing Lock = nothing
ground clamp on gray, probe on tan pressing UNLock = lights up

Hopefully this info nets us a nice simple solution, but I doubt I'm going to be that lucky, huh?

WhiteBird00

iTrader: (4)

Well, it tells us that you don't have a complete circuit when locking. Since the test light isn't polarity sensitive you're getting it to light up when unlocking because the clamp is taking power and the probe is providing ground. It also tells us that the problem is probably not in the lock solenoids.

There are two reasons you might not be getting a complete circuit when locking. First, there is something in the way the alarm is connected that interferes with the circuit. Second, the BCM is bad.

I'm still leaning toward the first problem but the only way to be sure is to disconnect the alarm and see if the locks start working. If they still don't work then the BCM is the probable cause.