1988 Suburban Door Locks

Hi all!

I have a 1988 Suburban, that was parked for 30 years in a barn. She's got some problems for sitting for so long. I'm slowly working through them.

I got the old girl 2 months ago, from a guy who got her 2 months prior from the barn. The original owner sometime before he parked it, put a new 350 in it, and converted it from TBI to carb'd. She's got a quadrajet on her.

My question is, she's got manual windows, but power locks. The locks don't work. Does that run through the computer on the truck? Or does it run outside of the computer. I don't have plans to hook up the TBI again, and if I do it'll be a holley or like EFI.

I'm doing window seals soon, and want to know if I need to look at replacing equipment in the doors while I'm in there.

Theres relays down behind the dash, kinda above where your feet are for the power locks, perhaps those are gone/dead

However during its conversion, the wiring couldve been cut? Who knows. Most frustrated tbi owners arent the type to understand how the system actually works, they just wildly cut everything thats offensive to them in order "restore" it to working condition

Simple powered circuit not through ECM. Check for power when solenoid in energized. If not present go upstream until there is power. Should also be power on the switch. Will work with key off.

Vbb199 said:

Theres relays down behind the dash, kinda above where your feet are for the power locks, perhaps those are gone/dead

However during its conversion, the wiring couldve been cut? Who knows. Most frustrated tbi owners arent the type to understand how the system actually works, they just wildly cut everything thats offensive to them in order "restore" it to working condition

Click to expand...

Surprisingly the wiring by and large has not been hacked. It’s still all there by my eyes. She did have a mouse infestation, but they attacked the seats rather than any wiring from what I’ve seen.

I’ll start trying to find a diagram for all the wiring then and supplying power.

Also do these auto locks lock the rear doors? Sorry for simple questions. 30yo here who grew up on the ranch wrenching on a 74 C10. Had plenty of squarebodies, but never a burn and I’m just too young to have grown up riding in the squarebody burbs. Rode a lot in OBS burbs and newer.

I have a 1989 Suburban with power locks. The ECU is in no way linked to the power door locks. The rear door does have a power lock motor as well as the 4 passenger doors. The driver side door unlatches with a small finger tab down at the lower corner and is not lockable (it can't be opened unless the passenger side is opened first), the passenger side rear door has the door handle with keyhole, and also will have a power lock motor (but no manual unlock from inside). If you look at the door frame on the passenger side you'll see the contact pads for the power lock there. There are no wires passing from the body to the door - when its closed the contact pads connect to matching tabs on the door so it cannot be power locked/unlocked when open. My rear door lock cylinder is broken so I can only lock/unlock with the power lock system. It IS possible to remove the interior trim and unlock it if the power system is dead and the key cylinder is broken, but it is a pain in the you-know-where to do.

Scoutmann said:

Surprisingly the wiring by and large has not been hacked. It’s still all there by my eyes. She did have a mouse infestation, but they attacked the seats rather than any wiring from what I’ve seen.

I’ll start trying to find a diagram for all the wiring then and supplying power.

Also do these auto locks lock the rear doors? Sorry for simple questions. 30yo here who grew up on the ranch wrenching on a 74 C10. Had plenty of squarebodies, but never a burn and I’m just too young to have grown up riding in the squarebody burbs. Rode a lot in OBS burbs and newer.

Click to expand...

30 years old here too

Yes the locks work for the rear doors also