Convert panic to relay on 2003 express

Hey, that would be pretty clever if you could do that! I worked on one of those vans before, and was just as surprised as you that they didn't also include a keyless entry on the remote. I have never done exactly what you want before, but I have some thoughts that ought to put you on the right track. In recent years, GM has been integrating a LOT of its electronics stuff together. I don't think that you are specifically going to find a "panic output" anyplace. Probably all of that remote stuff is integrated into the BCM (Body Computer Module). But remember, the panic button does what....honks the horn on and off, right? Well, let's consider the horn. The horn button (and also probably the BCM during panic mode) put out a ground......this ground goes to the van's horn relay......then the horn relay puts out a strong positive signal to operate the horn. If you don't already have a working knowledge of relays, you'll probably need to learn about how they operate before you'll be able to get this accomplished. The "Relays" link on the top left of this page is a good place to start. I can tell you that on your van, all of the lock/unlock relays are located in the fuse box under the driver's seat, and they are clearly labeled. I don't know where the van's horn relay is, but you'll want to find that. I can also tell you that the doorlock relays on your van need a positive trigger to operate. There's a harness coming out of the fusebox, going forward, that has a handful of small white and light blue wires in it----one or more of the whites there will be positive unlock. I hope I'm not being too long and drawn out here......I'm sort of thinking and typing at the same time right now. Hopefully I'm making some sort of sense. ---We know that anytime the horn is operated, positve power exits the horn relay (wherever that is), goes out underhood, and turns the horn on. We know that the horn operates when you press Panic. ---We know that you don't care much about the panic feature. ---We know that you DO care about being able to operate the horn while driving the van. ---You probably don't care if the horn works while the van is off, do you? So here's what you do. You just need one relay. Take the positive horn wire and split it so it operates the unlock when the van is off, but it still operates the actual horn when the van is on. So your first step is to find the positive horn wire someplace. I don't know where that is, but once you find the horn relay you'll be on the right track. Next, cut the horn wire straight in half. Wire your relay like this: 85: ground 86: ignition (any wire in the van that shows a positive when the key is in Run) 30: the side of the factory horn wire that is coming from the horn relay 87: the side of the horn wire that goes out to the actual horn 87a: the small white positive unlock wire in the van So here's how it will work: When the van is on, the relay is on. This means 30 and 87 are tied back together......meaning the horn works just like when the van left the factory. When the van is off, 30 is connected to 87a now. This means that whenever the horn tries to come on, it won't work, but instead the van's doors will unlock! Just two minor issues, but they probably won't bother you: -When you push panic, the doors are going to unlock over and over and OVER until you shut the panic back off again. But that's no big deal...... just hit panic once, then hit it a second time. And the panic times out after about 30 seconds, so you'll never kill your battery even if you make a mistake. -If someone pushes the horn button on the steering wheel while the van is off, the doors will unlock. Odd, but not bothersome. I hope this helps!

Maybe they are negative trigger locks; sorry about that. I've only done one of the 2003s. But you can always use another relay to convert the positive output from 87a into a positive. I've also been told you can get the lock wires coming into the kick panel from the door boot. (There is a set of blue and white wires right in the kick panel, but they are NOT locks....you have to go right to the boot...at least that's what I was told.) 1. I don't know how it is removed. But the cover illustrates all the positions, so at least that helps. I would imagine the seat is only held on with four bolts---I think it would be easiest just to remove the seat, if you need to. 2. I don't know where the BCM is. I suppose it's likely you could get away with playing with a test light, but I have never tried. I use the Power Probe, which uses LEDs instead of light bulbs, so it draws only a small amount of power...not quite as safe as a meter, but better than a lamp. But I've always been able to find a lot of components in cars just by listening for them. Temporarily unplug the horn(s) underhood. Then push the horn button or the panic button.....you should be able to hear the horn relay clicking on and off at that point. (Remember that when you push panic, you'll probably be hearing the parking lights relay pulsing as well.)

Chris said:

I've also been told you can get the lock wires coming into the kick panel from the door boot. (There is a set of blue and white wires right in the kick panel, but they are NOT locks....you have to go right to the boot...at least that's what I was told.)

Good to know, thanks.  I found some at the passenger side rear corner where they go into the back door.

I use the Power Probe, which uses LEDs instead of light bulbs, so it draws only a small amount of power...not quite as safe as a meter, but better than a lamp.

Good idea. I still use the same test lite I had from my auto install days. 

But I've always been able to find a lot of components in cars just by listening for them. Temporarily unplug the horn(s) underhood. Then push the horn button or the panic button.....you should be able to hear the horn relay clicking on and off at that point. (Remember that when you push panic, you'll probably be hearing the parking lights relay pulsing as well.)

Thanks for your ideas, Chris

Jack

Jack

The BCM is behind the panel where the glove box would be.