Power lock killing battery, help?

[Vbb199]

So, my 89 I've been working on has a leech somewhere on the electrical system.
Brand new battery, I've already replaced it once after a month or two because I thought it was faulty, so I ruled that out. It's not.

One day my power lock stopped working on the "lock" position.
It only unlocks now.

Shortly after that, the battery will not stay charged now, so I can reason that it is the power lock system.


Same thing happened with my old 90 suburban I had, brand new battery, guy I sold to had told me in convo it won't stay charged for more than a few days, but THE DAY I SOLD IT, the "lock" position/function stopped working on the drivers side door.

So, sounds like I'm getting to the root of the issue, faulty power locks.

That said, I unplugged both power lock switches on my 89 in case one or both were stuck in the lock position.

If I come out in a few days and the battery is still dead, I want to look into the relay/solenoid that might be the culprit next...


My question: can someone point me into the direction of where the lock solenoid / relay would be on a 89 suburban?


Thanks in a advance guys.

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[Goldie Driver]

See if this will help - I never could see or find mine, but it was not my issue anyhoo.

https://www.gmsquarebody.com/threads/power-door-lock-issues-resolved.26303/#post-499524

 

[chengny]

I had the same issue that is described - and illustrated - in the link referenced above. Only difference was my problem was with the PW's.

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This phantom view shows the layout and routing of the PW/PL harness. Item 15 is the PL relay:

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But if I could offer a suggestion, you might want to confirm that the PL circuit is truly the cause of your problem. Just pull the ORN/BLK lead out of the fuse block and observe battery charge for a few days. If the drain goes away, then you can start tearing into the wiring and components.

Battery power to the locks is always available at any of the 3 sockets in the bank labeled PWR (first full bank from the right). Yours might be in a different socket but will still be in the PWR bank.

Or, if you can live without the other 2 things that use that bank (the rear defogger and the tail gate power window), you can just pull the 30 AMP CIR/BRK from the fuse block. It will be labeled PWR ACC - it supplies the 3 PWR sockets above it. The bank of sockets may be also labeled with little "E's"

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[Snoots]

Make a gizmo.
If you can solder, take an old fuse (blown one) and solder a short wire to each of the prongs at the top. Then solder a #168 or #194 bulb to the other end.
Turn everything OFF.
One-by-one pull the fuses and insert your gizmo in place of the fuse.
If the bulb lights, that's the circuit that's causing the drain.

 

[Vbb199]

I just unplugged the P/L switches at the door to see the results, but I believe maybe it would be wiser just to unplug the whole circuit

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[Vbb199]

I do appreciate these suggestions guys... I'm inclined to believe there is more at play than simply a switch because I unplugged what I thought was the culprit switch (drivers) then proceeded to try to lock the truck with the passenger side, still no "lock" function.
I went ahead and unplugged both switches.

Will be a little before I'm able to get to it again, that said. I'll see if the battery died.

If it's dead still, then I'll start with you guys' suggestions and look deeper into it.

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[chengny]

I just unplugged the P/L switches at the door to see the results, but I believe maybe it would be wiser just to unplug the whole circuit

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The power locks and power windows are two entirely separate circuits. They do run along side each other, but that's as far as it goes. Power for the windows is supplied on a PNK wire that plugs into one of the two sockets in the fuse block that is labeled WDO.

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But that's beside the point. You are correct when you say, "I believe maybe it would be wiser just to unplug the whole circuit".

Because your battery is being quickly drained, you are looking for a broken wire that is shorted to ground (not just a broken wire) and that usually happens in either the flexible rubber conduit (that runs from the door frame to the outside of the cab):

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The other common failure point is at the rubber grommet that is inside the cab under the dash:

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[Vbb199]

Truck has sat for over 24 hours with just the power lock switches unplugged, battery wasn't drained.

Should be dropping off cold again so I can really put it to the test.

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[Vbb199]

The power locks and power windows are two entirely separate circuits. They do run along side each other, but that's as far as it goes. Power for the windows is supplied on a PNK wire that plugs into one of the two sockets in the fuse block that is labeled WDO.

You must be registered for see images attach

But that's beside the point. You are correct when you say, "I believe maybe it would be wiser just to unplug the whole circuit".

Because your battery is being quickly drained, you are looking for a broken wire that is shorted to ground (not just a broken wire) and that usually happens in either the flexible rubber conduit (that runs from the door frame to the outside of the cab):

You must be registered for see images attach

The other common failure point is at the rubber grommet that is inside the cab under the dash:

You must be registered for see images attach

The power lock circuit is what I believe is the culprit, that's why I unplugged it, just starting from the top of the circuit and will be working my way down.

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[Snoots]

You're probably on the cause but here's the gizmo I was talking about . . .

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[eskimomann209]

You're probably on the cause but here's the gizmo I was talking about . . .

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That’s a good gizmo. Can a test light do something similar?

 

[Snoots]

That’s a good gizmo. Can a test light do something similar?

Yes. It should.

For some reason I'm more comfortable using a bulb of the type that's actually used in the vehicle. But that's me

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[dvdswan]

That’s a good gizmo. Can a test light do something similar?

Test light is exactly what the gizmo is. Its just a lot easier to operate in a fuse panel than the test light is that has an alligator clip on the end.

 

[Vbb199]

Tomorrow since I won't be working, I will be checking the battery charge I haven't touched the truck since Tuesday.
Interested to see if the battery is dead or not.

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[chengny]

You're probably on the cause but here's the gizmo I was talking about . . .

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Sometimes the ground fault is intermittent. After the circuit that is causing the drain has been identified, the specific location of the short still needs to be found. This is often done by shaking/pulling/twisting the associated wiring in an attempt to intentionally cause the short. Depending on where the suspected short is (i.e. someplace where the fuse block can't be seen) or if working alone, it is a big help if the lamp is exchanged for a buzzer. That way you can be working underneath the bed or in the engine compartment and if you are able to get the short to occur, the buzzer will sound.