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I'm new here, so forgive me if this is a repeat post. I've searched the forum but found nothing like this problem. My 1998 Chevy Suburban power door locks work all by themselves. When I'm working in my garage with the Sub parked just outside, I can hear them locking and unlocking. (CLICK-CLICK; CLICK CLICK) This can be very embarrassing at a stoplight in downtown Atlanta and downright nerve-wracking when parking the Sub outside a hotel room at night. This will happen intermittently until it kills the battery. (My Sub sometimes sits unused for weeks)

I've replaced the master door switch on the driver's side and the problem got a little better, but came back to full song shortly later. I've searched and searched for the fuse that controls this, actually pulling EVERY fuse in the interior fuse block, but the locks do not stop working. Two local chevy dealers could NOT tell OR show me which fuse controls the locks and it is NOT the cigarette lighter fuse as many folks have told me.

Is there anyone out there who has experienced this, or even heard of it before? I do not have male pattern baldness, but I surely will if I can't find a fix for this.
 

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Hmmm, I had a similar problems years ago with an Olds car. It only happened when my wife came near the vehicle. She had a remote jammed into her purse and the buttons were always pushed.

There maybe a circuit breaker instead of a fuse. I do know, you should have two relays, one marked LOCK and one marked UNLOCK. Maybe one is stuck in the operated position.
 

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Discussion Starter #3
Latest development with self lock-unlock problem

Hmmm, I had a similar problems years ago with an Olds car. It only happened when my wife came near the vehicle. She had a remote jammed into her purse and the buttons were always pushed.

There maybe a circuit breaker instead of a fuse. I do know, you should have two relays, one marked LOCK and one marked UNLOCK. Maybe one is stuck in the operated position.
Thanks RayVoy. Here's latest: I completely unplugged the new 'master window/door switch' thinking it should disable the locks, but no sooner had I put panel back in door and the loc-unlocking began again! There is a faint sound of clicking coming from behind the ashtray area. I'm wondering if the relays you mention may be located there. My Haynes manual wiring diagrams do not show much in the way of 'locations' of relays and such. Still scratching my head.
 

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you should have two relays, one marked LOCK and one marked UNLOCK. Maybe one is stuck in the operated position.
@98Subdriver........I've given you the incorrect info. The circuit with 2 relays is the power windows, there is an up relay and a down relay.......Sorry.

The door locks only have one relay. It is on the inside the dash fuse panel. Here is a pdf of your owners manual. Look at page 6-63, the relay is described on 6-65.
 

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Discussion Starter #5
I will check my owners manual (?) but the Haynes service book wiring diagram shows both a relay and a 'door lock control module'. Talking with chevy service techs locally (?) I've been told this 'module' was under the jack in the left rear of the sub, but there is nothing there but the jack. Advance and Autozone do not list a door lock control module for this vehicle so you are probably right. (I wonder where Haynes gets their diagrams?)

I'll let you know what I find about the relay... Thanks!

- - - Updated - - -

you should have two relays, one marked LOCK and one marked UNLOCK. Maybe one is stuck in the operated position.[/QUOTE @98Subdriver........I've given you the incorrect info. The circuit with 2 relays is the power windows, there is an up relay and a down relay.......Sorry.

The door locks only have one relay. It is on the inside the dash fuse panel. Here is a pdf of your owners manual. Look at page 6-63, the relay is described on 6-65.
You are absolutely right RayVoy, now we're making a bit of progress. I can now at least DISABLE the errant locks, which indeed helps. It also revealed another interesting item. With the "A" circuit breaker removed, the door lock switch does NOT operate the locks, but it DOES illuminate my courtesy lights inside the car, on the doors, for as long as you hold the switch button down! Strange indeed as it did not DO this with the circuit breaker in place. Any ideas?
 

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You are absolutely right RayVoy, now we're making a bit of progress. I can now at least DISABLE the errant locks, which indeed helps. It also revealed another interesting item. With the "A" circuit breaker removed, the door lock switch does NOT operate the locks, but it DOES illuminate my courtesy lights inside the car, on the doors, for as long as you hold the switch button down! Strange indeed as it did not DO this with the circuit breaker in place. Any ideas?
Ok, "A" is a circuit breaker, I jumped to the conclusion that it was a relay..

I wish I had a copy of your wiring diagram.

Ok, maybe you do have a "module" somewhere. On my truck, it is under the switch assembly on the driver's door. If I remove the inner door panel, the module is inside the armrest, under the switches. But, I think you said you changed the switch assembly, if the module was there, you would have seen it.

On the Burb that is the same as mine, there is a rear hatch/rear door lock module on the rear liftgate, could yours be there?
 

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Just throwing this out there as a remote possibility. If the vehicle was purchased used or you just so happen to be missing one remote for it, there may be a remote that slipped down into a crevice. It *could* have sat there for months or years and then when you go to move a seat or adjust something, the remote button gets activated and is riding on the brink of the button on/off.

I know it's a remote possibility (pun intended for fun) but it *could* still be a possibility.

Tom
 

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I doubt there is one single solution for this kind of problem. I will note that I once had this exact problem on my Bronco II. I was lucky enough to track it down to a connector near the battery. While filling the battery with water, I had spilled water and somehow got this connector wet, which was causing it to short out and continuously trigger the power locks. The fix was to wait a few days for the connector to dry out and everything returned to normal.
 

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It has been doing this for over a year before it was sold as scrap, the scrapper detailed it and sold it to me for $300 more then he paid. The locks will unlock and lock when there is absolutely no activity, parked for hours, ignition off or on running or not and now the dome lights are doing it too but not in unison. I take it there was never a resolution found to 98subdriver's problem.
 

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Ok heres a thought.... to program the key fob on these trucks you take a paper clip or wire and jump pin 4 & 8 on the obd2 port, which cycles the locks. As soon as they are connected the locks cycle, then one presses both button on the fob until the locks cycle again, pull the paper clip and your done. I bet this is where the problem lies. At the obd2 plug. Maybe its all dusty and or had coffee spilled on it or some ****.

Al
 
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very early 1999, and yes it does have electric mirrors and windows, which I have fixed on the driver's side, the lock actuator of the passenger side rear was unplugged, plugged it in and now it has joined the rest with the self locking/ unlocking at random. I think it may be that one of the actuators is not fully unlocking or locking which may be triggering all of them to keep trying due to a power drain or fluctuation triggering the relay. Could a weak actuator cause this? By the way... where is the relay? is it hidden somewhere under the dash? Buying a chitlin manual tomorrow, but they usually are worthless.
 

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As for the lost key fob, no such luck! Looked over every inch of the old girl. The fob I got with it has a stone dead battery that I am replacing in the morning.
 

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Okay,

To get the door locks to work, the door lock actuators have to be grounded to activate and the output signal side of the master switch has to send a power signal when the door lock switch is applied

Since all the actuators are going off at the same time tells me there is a intermittent power signal "after" the switch to activate all the actuators. If the drivers door lock switch pulled out of it's mounting, is there any battery voltage coming out of the white or light blue wires at any time without the switch being touched??? I will leave a schematic to start tracing down circuits.

This statement concerns me as to the potential problem: "which I have fixed on the driver's side, the lock actuator of the passenger side rear was unplugged, plugged it in and now it has joined the rest with the self locking/ unlocking at random". It's tell me why was the passenger side rear unplugged??? What was touched, or not installed correctly to generate this problem??? Was this vehicle in a major broadside collision???

First diagnostic step, remove the power door lock master switch, does that stop the problem??? Report your findings.

Door Lock Wiring 2000 Suburban.gif
 

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The last owner tried for a year to get two problems fixed then gave up and scrapped the whole rig. I bought it from the scrapper. I talked to the scrapper again last night since he got another 1999 Suburban in for scrap. First, he told me that the last owner unplugged the passenger side rear so that they could always get in even if it decided to lock them out, second, the Suburban refused to start and the last owner did a complete tune-up, fuel filter change, fuel pressure check, and finally when the scrapper showed up to tow it, the scrapper tried a puff of starter fluid and she started right up and ran great, even started the rest of the day. I am assuming the fuel pressure regulator is faulty, and will be installing a new one asap. The second Suburban I am getting from the scrapper reportedly had a leaking rear main seal. Upon inspection it seems that fuel is pouring out the rear of the intake cover area and also seems there is no oil loss at all. Again I believe that either the seals at the fuel line to injector are leaking or the fittings attaching the fuel lines at the rear of the engine by the fire-wall are loose. Thanks so much for the diagrams and the explanations. While I have your attention... where is the door lock relay located? I have heard so many differing opinions, including that it does not have one, and what fuses disable the locks if any. Keep hearing it is #13. A third 1999 Suburban I might be getting has water in the oil but no steam in the exhaust (blown head-gasket or cracked head) and the trans slips instead of kicking into OD . I am assuming that it is a good chance that the shift solenoid may be sticking.
 

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Seems to me I read something about the locking relay being located near the middle of the dash, but against the firewall. I’d trace the leads from the door jamb to verify. The older trucks had a small harness of the lock and window controls running between the doors that sourced the passenger door. May even be tucked just behind the front edge along the bottom frame pipe.
 
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Cowboy is on point, now for the illustrations to get you in the area. Enjoy twisting the chit out of your back.

Hope some of this is helping you. Make copies to your computer for future reference.

Door Lock Relay 1999 Suburban 02.jpg
Door Lock Relay 1999 Suburban.jpg
 

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Thank you so much! So the remote pickup is on driver's side of center and the main relay is passenger's side of center. I unplugged the driver's side switch at the door and all the locks work with the passenger side switch still but don't seem to be demon possessed. I am assuming the driver's main switch is flaky. Any chance that it can be disassembled and cleaned or is it some chip or diode that may be at fault.
 
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