So you're going with the top configuration with the 3 wires same as yours, makes sense to me, that's what I'd try first. The only query is the red wire, common may not be straight to battery, without seeing the cct for the "original controller". If you can't determine if there's anything between common and battery maybe better to run the red to a known positive battery via a fuse, probably only a few milliamps.

I found a diagram, for an 84 Chevy Coupe. I've got an 88 Chevy Van but the switch looks the same. Unfortunately, my Van is getting the air conditioning replaced cause the idiot up the road put the wrong gas in it, so can't test it. But will test first.

Seems like it's gunna work. I'm assuming the orange wires in the diagram and "hot all the time" means the common wire on the switch is positive

Ok, I think I'm starting to grasp what's going on. Well nearly.

The other dumb question I've got is about the antenna. Will this work if the unit sits in the door panel?

Does the antenna need to be visible?

I don't even know what technology this switch uses.

decrepit said..
Looking at your chevy diagram, I think you can go with your "red to common" idea. Although it's fused at 20A that will probably blow the unit to smithereens if you get a short, I'd add an inline fuse to the red wire, 100mA or 0.1A should do it.

I have my doubts about antenna in door panel, might work close up. The external steel panel is going to block RF fairly well, but the internal door panel probably isn't steel, the antenna may get enough signal from internal reflections.
If you can't find any instructions, it's going to be, "suck it and see."

Don't go for the red to common.......... The connections I have described will pick up the correct voltage refernce to switch, no further connection to + or - is required... Definitely put an in line fuse in the red + connection to the unit though.

Smithy said..



Don't go for the red to common.......... The connections I have described will pick up the correct voltage refernce to switch, no further connection to + or - is required... Definitely put an in line fuse in the red + connection to the unit though.

Well, surely "hot at all times", is +ve battery? Why go to the trouble of going anywhere else?
Unless the battery's a positive earth scenario, and that's easily checked.

Shouldn't connect the 2 Because you have a control circuit that is mA and if the Chevy diagram is correct, a door actuator circuit that is fused at 20amp. The unit is designed to keep the control and door circuits seperate to protect each. If you connect them together the unit will have to be fused at 20 amps which will not protect it and creates a fire hazard as the electronics burnS in the event of a fault...

The other issue of commoning the 2 up is that the electronics may get a switching transient spike when the door actuators operate, this spike can cause the unit to malfunction. If the power supply is seperated and only common closer to the battery this issue is reduced.

as far as going anywhere else, not sure what the issue is, connect a fused 12vdc power supply and run 3 wires to the existing locking switch...

Ok, got it all working. Well almost. I just want to do one more thing.

I've got a purple wire that connects to the parking lights. I've found the right fuse and will tap it into the hot side of the fuse.

My question is: If I attach it to the parking lights, is there a danger when the parking lights are on that it could send power back up to my keyless unit causing problems. I'd assume it's probably protected - but for $15 you never know.

As an extra safeguard, and a newby question what type of diode should I attach to ensures the current only goes in one direction - ie from my keyless entry device to the parking lights and not the other way around, when the parking lights are on?

oliver said..
I can think of one reason. And I've come across it before and I think it's a reasonably common problem in older cars. May not apply to my central locking though.

When I replaced the sealed beam headlights with the superior halogens. My high beam used to flicker after about a minute. I fixed this by installing relay switches for my headlights and the high beam. The reason is because the wiring is all over the shop, the wires in older cars are too thin/become worn and the small switches in the indicator stick were not designed for new increased load placed on them running the highbeam and the headlights. Installing relays reduced the load on the switch.

Yeah, this is normal back when cars didn't have a 1001 relays. When new the switch contacts don't have a problem passing the needed current, but when worn and pitted they do. So every car now seems to have a relay driving almost everything with a decent amount of current.

oliver said..
Ok, got it all working. Well almost. I just want to do one more thing.

I've got a purple wire that connects to the parking lights. I've found the right fuse and will tap it into the hot side of the fuse.

My question is: If I attach it to the parking lights, is there a danger when the parking lights are on that it could send power back up to my keyless unit causing problems. I'd assume it's probably protected - but for $15 you never know.

As an extra safeguard, and a newby question what type of diode should I attach to ensures the current only goes in one direction - ie from my keyless entry device to the parking lights and not the other way around, when the parking lights are on?

Please don't connect the keyless entry system to the hot side of your fuse. At best nothing will happen, at worst (if the keyless entry system switches the negative) you'll blow the system up.

The fuse is normally always powered, the switch and lights come after the fuse. So you need to connect your wire elsewhere, probably after the switch if positively switched. You'll have to check to see whether your system is negatively or positively switched.