OEM Elect locks on a 99 Chevy Suburban

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  #1  
Old 02-11-10, 02:14 PM
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OEM Elect locks on a 99 Chevy Suburban

Only 1 door works on my Sub, the rear passenger door when I use my key fob. None of the other locks including the tailgate work either. Lock or unlock. Driver door lock button does nothing when pushed while passenger door lock button works on the one door that he key fob does.

Is there a fuse that is only the driver door button? Why would only 1 door work and all others not? How do you test/replace these locks?

thx
 
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  #2  
Old 02-11-10, 03:05 PM
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My wife has a 98 chevy astro van with a rear hatch. Not the same vehicle I know, but same maker and roughly the same year so maybe this will help anyway.
When trying to find the trouble with the lock for the rear hatch, I discovered a blown fuse marked "accessory". Basically, the fuse controlled the cigarette lighter, other accessory plugs, and apparently the rear hatch. Even though it is a pretty big deal, the fuse panel said absolutely nothing about the rear hatch. I replaced that fuse and the rear hatch worked again. Now I've learned the first thing to do when having problems with door lock switches is to check all the fuses, even the ones that seemingly have nothing to do with the problem. That's what I'd do if I were you. Good luck.
 
  #3  
Old 02-11-10, 10:08 PM
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This could be a tricky one so got you a description of how the system operates.There is one fuse in the power dist box marked for cig lighter that supplies power to the system there is also a circut breaker that supplies power to your system marked accessory. These both feed the module located in the d piller on the rh side (the door jam for closing the pass rear door) about mid way up and supply hot to the relay
here is the description
Notes

POWER DOOR LOCK SYSTEM DESCRIPTION
The power door lock system incorporates door lock switches on both front doors and on the RH D-pillar, door lock motors in all passenger doors and in the RR cargo door, a door lock relay and a door lock control module.

Power for the door lock switches and the door lock control module is supplied from the CIG LTR fuse 13 through CKT 640 (ORN). Power for the door lock relay is supplied from the PWR ACCY circuit breaker through CKT 540 (ORN). Ground for the door lock relay is supplied from G202 through CKT 150 (BLK) and ground for the door lock control module is supplied from G400 through CKT 150 (BLK).

The door lock motors are reversible and both sides are connected to the normally closed contacts of the door lock relay. Those contacts of the relay are connected to G202. When any of the door lock switches are placed in the lock position, voltage is supplied through CKT 195 (LT BLU) to the relay lock coil. Since the other side of the lock coil is connected to ground, the coil is energized and it pulls the lock contacts closed. Voltage is then supplied through CKT 295 (GRY) to all the door lock motors and the doors lock. The unlock function operates in much the same manner except that when any of the switches are placed in the unlock position, voltage is supplied through CKT 194 (WHT) to the unlock coil of the relay and CKT 294 (TAN) supplies voltage to the apposite side of the door lock motor and the doors unlock.

DOOR LOCK CONTROL MODULE DESCRIPTION
The door lock control module is used on vehicles equipped with cargo doors. The purpose of the module is to lock the cargo doors after a lock cycle has been commanded from any of the door lock switches with the cargo doors open. When the RH cargo door is open, the module receives a ground signal from the closed contacts of the rear door jamb switch on CKT 1897 (ORN/BLK) to G400. When a lock command is received, the module retains this input until it receives an open input from the rear door jamb switch. Then the module sends a lock command through CKT 194 (WHT) to the door lock relay and the doors lock.

REAR CARGO DOORS DESCRIPTION
The power door lock motor will not operate unless the rear cargo doors are fully closed. The power door lock motor is in the right cargo door. The contactors are on the rear cargo door opening on the body and on the right cargo door.

I can send diagrams via e mail can't post due to locks on the files from my information sources so no simple hard wiring anymore.Did this happen all at once or over time?My thoughts are running toward this being caused by bad lock sols or wiring corrosion at the plug ins for the module since one is working and the others are not. If you dont have the rear cargo doors the system operates the same with the exception of the Body Control Module takes the place of sending the sig to the door locks instead of the door lock module.
Good Luck
 
  #4  
Old 02-12-10, 07:52 AM
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Thanks for the info:
It happened over time, first the rear cargo door lock button, then the passenger doors locks then the driver door lock button. I bet there is a ground wire issue somewhere, hard to believe 3 of the 4 locks have failed...Any chance the module in the rear door is shorted? Hate to to replace the sol only to have it be the main mod. Can I put an Ohmeter on the sol and push lock button and measure for current? If no current it would be fuse or module right??

I see the solinoids are ~$25 each I would really like at least to replace for the driver door. How easy is it to get to the lock solinoids? Just pop off door panel? or do yo need to do more?
 
  #5  
Old 02-12-10, 01:37 PM
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Yep fairly easy to do, pull the door panel and the water barrier under it. the sol is located in line with the handle on the inner door frame.Unplug the sol and test for power use a common ground and test both pins on the wire harness,as for replacement.Simple unbolt and and remove the actuator arm also a good test for the module as well.I've got the feeling that since this was over time that they went one at a time and the module isn't your problem.But have had stuff bite me in the past.
Good Luck
 
  #6  
Old 02-12-10, 02:14 PM
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Thanks...

Do I replace the water barrier and what would you use? Older car so maybe not so worried about the water barrier but if there is an easy solution.....
 
  #7  
Old 02-12-10, 04:43 PM
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You could have multiple problems?

First check ALL fuses (easy to do as opposed to ripping the doors apart). Your owner's manual should show you the location of all fuse boxes. Some vehicles have 3 different fuse boxes! Under hood, by driver, and by passenger.

How to test fuses...
Testing fuses Page

Just take one fuse out at a time, test, then replace. It is easy to get them mixed up, so just one at a time.

Then are you driving the vehicle in a dusty environment with the windows down? Some GM electrical switches I have seen not working are "open to the air". Dust can easily get inside and this keeps the electrical contacts inside the switch from making contact. If you are "mechanical", some of these switches can be taken apart and cleaned. Or easily replaced.

You can test the switches with an ohm meter or continuity tester just like for the fuse testing above. You would just need to have the tester on the right connections for testing. If you are an "electronics type", you could probably figure out which connections were which on the switch. Otherwise complete testing instructions would be in a factory service manual set which you can order from a dealer or helminc.com

Then the electric door locks can be tested with a multimeter set to DC volts 20 (or next higher range above 13 volts). Activate the lock and see if your have power at the lock.

As to replacing the electric door locks, some of these in older vehicles are a royal pain to get at and replace. Riveted in! And you need to remove the outside door handles to get at them. (I don't know about your year vehicle???)

Anyway I would suggest going to a wrecking yard and finding a similar vehicle. Hopefully you can find one with the door panel off. Then see how the panel comes off and see how you would get at the door lock. And take tools and try removing a door panel there first. If there are plastic clips which hold the panel on, might want to grab a few of those. A few of these always break when I remove a panel.

Also if you are taking the electric door locks from a wrecking yard vehicle, be sure to take wire cutters. I've seen some which don't have any electrical connectors. So you need to cut the wires to get them out. (And also drill out the rivets - cordless drill).

(See why I said to check the fuses first! )
 
  #8  
Old 02-12-10, 05:13 PM
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You can reuse the barrier just might have to tape it back on; it may tear in places when removing no big deal. I use the handymans friend duct tape since this is a no show item and it holds well.
 
  #9  
Old 02-15-10, 05:27 PM
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Bill- it is a 99 model suburban with panel doors.
 
  #10  
Old 03-14-10, 12:17 PM
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So it WAS fuse 13 that was blown. I replaced it and the lock switch on the driver side and the switch in the rear cargo started working again!!!

Well. kinda. They make a clicking sound you can hear in the fuse area and at each door. BUT, the door locks dont work. The driver side rear door works on occasion but non of the others. The lock might move up or down a little but they dont fully lock/unluck. Its almost like they are not getting enough power. Car is running so it is not batt. Is this a loose ground somewhere? Are all the lock sols bad? It seems unlikely with it being a 99 and not used alot. Whats next from here?

thansk
 
  #11  
Old 03-14-10, 12:40 PM
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If its not used often..its probably got some corrosion and crud on some of the rods/linkages in the doors...or depending on the actual solenoid mechanism..they may be crudded up. I found that my "solenoids" on my Mazda are really motor driven actuators...not solenoids at all.

I just messed with the locks on my nephews '97(?) Suburban.......what a freaking nitemare! You need arms like a squid to get to some of the connections..and thats if you take the glass out. Even trying to remove the latch mechanism is insanely difficult...and I've got skinny arms!
 
  #12  
Old 03-14-10, 07:10 PM
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Do the above and the following might also be a problem...

I don't know about the 99 burb, but on older models, the electrical switches have openings in them...

And if you drive on rural dusty roads with the windows down, all that dust can get into the electrical switches!

Then you can get a poor electrical connection. And this would be the same behavior as a low battery.

On older burbs I have been able to take apart some of the switches, clean them, and dab on a bit of dielectric grease (sold at auto parts stores).

You can clean electrical contacts with a pencil eraser or electrical contact cleaner.

Also electrical connectors can become dirty and also have similar symptoms. The electricity does not get through.

These things are like a dirty loose battery connection. You clean the connection on the battery, then the car starts right up! Same thing.

You can test for this with a voltmeter (multimeter), it is called a voltage drop test...
How To Perform A Voltage Drop Test - Help With Automotive Circuit Diagnosis
 
  #13  
Old 03-14-10, 07:26 PM
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Originally Posted by Gunguy45 View Post
If its not used often..its probably got some corrosion and crud on some of the rods/linkages in the doors...or depending on the actual solenoid mechanism..they may be crudded up. I found that my "solenoids" on my Mazda are really motor driven actuators...not solenoids at all.

I just messed with the locks on my nephews '97(?) Suburban.......what a freaking nitemare! You need arms like a squid to get to some of the connections..and thats if you take the glass out. Even trying to remove the latch mechanism is insanely difficult...and I've got skinny arms!

so....do I go for it and try to fix or just stick with manual locking.....

I love a challange but these doors can be a pain in the butt.

Any pros out there have any hints how to do this easier?

thx
 
  #14  
Old 03-14-10, 07:35 PM
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If it were my vehicle, I would put this project off until "later"

Then some nice spring day, I might get motivated and do one door...
 
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