Help me diagnose my power door locks please

[Rafs]

1997 Yukon 2 door with barn doors:

Driver door works manually, with the switch, and with the fob. Fob and switch do nothing for the passenger door or rears.

Passenger door only works manually. The switch does cause the driver door to lock/unlock but not the passenger or rears.

Barn doors: Switch locks/unlocks the drivers door and I hear the solenoid firing in the barn door.

What's my next step, thanks!

 

[OR VietVet]

On that old of a vehicle, I would check the umbilical cord wires that pass thru at the door hinge area. They get folded and flexed repeatedly over the years and can cause the wires to rub thru or break inside that flexible conduit.

 

[Eman85]

Barn doors have an electrical set of contacts at the upper part of the door instead of hard wires. They can become corroded and not make contact. you can clean the brass contacts and see if that helps. After 25 years there is a good chance the actuators just gave up. Not expensive just a pain to change.

 

[Matthew Jeschke]

I am having same problem. I will check the door connector by a and b pillars. I've actually refurbished most of the truck, re-taped and checked most of the harnesses. I know I've done the inside of the doors, and disconnected the harnesses to take the doors off... I'll double check the pillar connectors.

Problem is intermittent but for some odd reason pulling relay and putting back in seems to fix it for a short while.

Another question, the locks don't seem to operate with great authority when they do work. Just well enough. I wonder if I could do an impedance test? Any idea what load the actuators typically present at the unlock relay terminals? What a single actuator presents?

New video by Matthew Jeschke

photos.app.goo.gl

 

[Eman85]

20+ years of dirt and grime along with corrosion at electrical connectors doesn't help. The actuators get weak and the linkage gets harder to move.

 

[Matthew Jeschke]

Yeah I was thinking of getting all new actuators. Probably worth it, or at least cleaning them if is possible.

One thing I like much better about the next body style from the NBS, gen 2 Tahoe is the better door seals.

 

[Eman85]

If you pull the panels clean and lube everything. The design of the inner door SUCKS if you ever need to pull it apart.

 

[Matthew Jeschke]

Dang these door lock actuators are $$$$

RockAuto has their "economy" options which I seldom if ever buy, it's $28.79 otherwise Looks like $118.89 for a "daily Driver" quality.

The first is a "Shee-mar" brand. Never heard of it. The second is "Standard Motor" which I've never purchased. Is this stuff any good? I typically only get the OEM parts but it's $168.89 for one of those.

My plan is to buy one, inspect it. Then take apart some used ones and rebuild them / refurbish them. I have rebuild all kinds of weird stuff, like the HVAC actuators, Radio, Seatbelts, etc.

 

[Mean_Green]

As noted, first step is inspect and lube. Some sort of spray lube to get to all of the actuator and lock linkage. Lockeze inside the keyholes and operate the keys several times.

My doors all worked when I first got it, but the cargo door lock assembly was stiff with the key and didn't work electrically. Lube fixed both. Door lock solenoids/motors don't have a lot of force and if the lock itself is bound, they won't do much.

 

[east302]

The first is a "Shee-mar" brand. Never heard of it. The second is "Standard Motor" which I've never purchased. Is this stuff any good? I typically only get the OEM parts but it's $168.89 for one of those.

If it helps, I did put a Standard actuator in a few years ago and it still functions (2017, 20k miles). These are all coming from China (or Taiwan if you’re lucky) so keep expectations low and you won’t be too disappointed.

I’d 100% skip the $7 Sheemar actuator and anything made by Dorman. I’m like you, though, and would get the original GM part when possible. Let us know if you tear one down - I’d be interested in what you find.