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1998 GMC 4-door Power Door locks

Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=22651
Printed Date: July 09, 2025 at 7:39 PM


Topic: 1998 GMC 4-door Power Door locks

Posted By: jeffl
Subject: 1998 GMC 4-door Power Door locks
Date Posted: December 10, 2003 at 11:30 AM

My door locks have been acting strange.  It has both remote entry and the usual power locks inside. 

If I use the power locks then it will continue to lock/unlock/lock the doors rapidly, this may continue for a few minutes without touching them again. (sometimes I can hear the relay under the dash toggling very fast.) The same holds true if I use the key to open the hatchback window...toggling door locks.

The remote will sometimes work as long as this toggling relay has stopped (as described above).  I found 2 fuses in the fuses: a 5A labeled "mir/lcks" and a 15A labeled "pwr locks".  I removed the 5A and the remote entry works fine now, but obviously the power door lock button no longer function and the fast chaning relay has stopped altogether.  When I put the fuse back, it starts toggling all over again.

Could it be just a bad relay causing all this?  The relay can really start to switch fast and it is so strange because it may stop for a few seconds and then it just picks right back up and starts toggling all over again.  My only other thought a a loose connection or ground? 

Any help is greatly appreciated.

Jeff




Replies:

Posted By: draasch
Date Posted: December 11, 2003 at 11:03 AM
yes it could be the relays....doule check the switches...did they get wet???

the contacts could be shorting out....

-------------
Good Luck
David
Ace Security
813-376-9778
Tampa
Donate to the 12volt





Posted By: jeffl
Date Posted: December 12, 2003 at 9:18 AM

Thanks for the reply. 

It was raining on the day they quit, but it was garaged, so I guess I can count that one out.  :)       I pulled the controls out of the door, didn't see any loose connections. I don't have a diagram, so I'm not sure which wire is which, but I'm searching for a diagram now.

 Can you tell me where the relays are located?  Usually they are right beside the fuses, but they must be behind the dash somewhere?

Jeff





Posted By: draasch
Date Posted: December 12, 2003 at 11:35 AM
Power Lock L BLUE DRIVER KICK #203
Power Unlock WHITE PANEL ** #202
** Without OEM Keyless Entry See Note #203. With OEM Keyless Entry See Note #202. #203 - See Reversal Rest At Ground Door Lock Diagram. #202 - See Positive Pulse Door Lock Diagram.

if you do not have a factory keyless, there are no relays.

-------------
Good Luck
David
Ace Security
813-376-9778
Tampa
Donate to the 12volt





Posted By: jeffl
Date Posted: December 20, 2003 at 2:51 PM

After leaving the fuse out for a week and replacing it this morning, the locks are behaving normally.  I still tend to search out this problem.

I do have both keyless and door switches to lock the doors.

I appreciate your help.  It is nice weather today and I'm going back outside to try to find the problem.

Jeff





Posted By: jeffl
Date Posted: December 20, 2003 at 3:44 PM

Well, after doing more checking, now the rear hatch button does not work on the push-button located on the outside of the truck, the inside button on the dash works and so does the remote button.  I have a feeling there must be a loose connection or faulty switch in the push button. 

Jeff






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