adding lock motors to 2002 silverado

2002 Chevy Silverado with factory key-less entry. I want to add two universal lock motors to the system. I have them in a bed mounted tool box. Desired action is for the tool box to lock and unlock with the doors from the factory remote. My concern is that since there is a Body Control Module and a Door control Module involved, I don't know if I can wire directly into existing lock/unlock wires. Is it as simple as adding relays to control the added lock motors, one for lock and one for unlock?

Yes, here's a diagram, tap the light blue lock (+) and the white unlock (+), both at the brown plug in the BCM adjacent to steering wheel. Note the two diodes as a safety precaution to protect your BCM. Lock and unlock outputs to 86. Ground to 87a and 85. 12V+ constant 10amps fused to 87. Actuator wires to 30. silverado.bmp

Do those wires respond to the factory keyless? Pretty sure that is via the lock/unlock switch only. Maybe I am wrong, but tapping into the drivers door, or drivers rear door if it is a crew cab, will get you the motor wires to which you can add up to 2 additional actuators to. Just tie the new actuator wires to the factory wires and hit the button. If the action is reversed simply reverse your leads and it will work with both the switch and the keyless.

If the wires listed by Howard test with the keyless, then follow his diagram and forget you saw my reply

To master and control electricity is perfection. *evil laugh*

Hmm let me revise that statement, The motor wires need to rest at ground in order to simply tap into them. One stays grounded while the other switches to 12v. The actuator moves one way. Then that wire stays ground while the other switches to 12v and the actuator moves the opposite way. Sorry for the confusion!To master and control electricity is perfection. *evil laugh*

James, I used Directwire for that info ref. keyless, they gave the body control as the location with colours, but those same wires are probably in the DKP. I haven't even a clue what a Silverado is! The answer of course is test and I thought of the trigger with added relays and diodes so the body control wouldn't "see" it and go into doodie mode.

I figured as much Howard. The silverado is chevys full size ck 1500 series truck line here. Those wires are the positive inputs from the drivers door lock switch to the bcm. Hence why I wonderec if they even respond to the keyless signal being processed by the bcm elsewhere. Gm was nice enough to leave a disarm wire at the bcm up until 03 I believe. Makes life easier and cheaper for us doing add on keyless. Anyways back to the OP topic, if those wires respond to the keyless signal then Howards diagram will work fine. If you only want the new actuators to work with the door lock switch inside, it will definitely work fine. We do this type of thing pretty routinely on the big 3 (ford chevy and dodge) when adding a LEER or ARE fiberglass topper. They can be equipped with an actuator to work as described here, and they actually tell you to go to the drivers door motor wires. Haven't had any issues reported and I have been doing that for at least 3 years. To master and control electricity is perfection. *evil laugh*

Just proves the old adage many ways to skin a cat! Same with add-on air horns. Do you pick up from the switch? Before the relay? After? or just tap the wires and increase the fuse rating. I've done ALL of the above. Nothing wrong with your method, since I was in unknown territory and have seen so many people doing GM stuff with R/S, failing to power up an ACC then the vehicle throws DTCs all the time. In the early 90s, Maximas over here had a switch rather than actuator and switch in the driver's door, I did exactly what you do on two I owned so there's no real problem if you know the vehicle.

Hmm this is what I get for not fully reading my info. The drivers door lock and unlock motor wires are in the same brown plug at the bcm.

Drivers lock motor wire - Gray - at Brown plug on BCM

Drivers unlock motor wire - Tan - at Brown plug on BCM

If the wires are larger than the rest of the wires, just tap right into them at the BCM.

To master and control electricity is perfection. *evil laugh*