YADLT (Yet Another Door Lock Thread)

[KelOfTheRockies]

I did search and read, but my problem has elements of several other complaints plus a callback to my thread about burning up the rear hatch cable harness.

Truck is 2000 Ltd with 238,000 miles

So, to recap, a couple of weeks ago while driving home at night, I smelled strong burning wire insulation odor. No visible smoke, but the odor was overwhelming
Got home without fire, but was scared of a burst of flames for the last fifteen minutes of driving. Upon parking, I disconnected the battery and turned in for the night.

Problem turned out to be wire/insulation failure in the rear hatch harness, where the common wire breakage occurs. Best I can tell, no fuses popped, but there was severe wire burning:

I got a couple of harnesses from salvage and spliced in good wire, cut from the hatch end to the connector pin, so only one splice per wire. Finished repairing all the damage - which turned out pretty good - and installed the harness.

Rear window, brake light, and wiper all work now.

Problem is the locks don't work. They got squirrelly when the near-fire happened and I was hopeful the repair would bring them back online. Here're the symptoms:

• Pressing driver arm rest button or keyFob "Lock" button locks the driver door only.
• Pressing driver arm rest button or keyFob "UNLock" does nothing; no action no sound.
• Pressing KeyFob "Lock" button does not cause a beep.
• Pressing KeyFob "UNLock" button beeps twice, as normal, and flashes the lights (but, again, does not unlock anything).
• Pressing the passenger arm rest button "Lock" locks the driver side only.
• Pressing the passenger arm rest button "UNLock" does nothing, no sound no action.
• Manually unlocking the driver door with the key works, but am unable to lock the door - the key won't turn clockwise; like the tumbler is jammed.
• Passenger door can be locked or unlocked with the key
• Locking all four doors by manually pressing each lock-button on the sill, and then locking the hatch door with the key actuates the alarm.
• Unlocking the hatch with the key disables the alarm
• Unlocking driver or passenger door with the key disables the alarm.
• All windows work from the driver arm rest buttons.
• Hatch window works with the key, and from the dashboard button.

Any input on how to troubleshoot this is very much appreciated!

—Kel

 

[brillo_76]

Does the 1999 have the fob control in the rear door hatch? I am suspecting meltdown may have affected that module too. The early years its under the drivers seat I am not sure if its under the seat or in the rear hatch on a 1999.

That were I would start testing anyways. Verifying its working properly. As the fob controls go through a controller.

 

[KelOfTheRockies]

Does the 1999 have the fob control in the rear door hatch? I am suspecting meltdown may have affected that module too. The early years its under the drivers seat I am not sure if its under the seat or in the rear hatch on a 1999.

That were I would start testing anyways. Verifying its working properly. As the fob controls go through a controller.

I wondered about that. There is a controller-looking box inside the hatch door, to which one end of the burned harness attaches, and I was afraid it may have been damaged by the short and resultant astronomical currents.

I was hopeful that, because the window, wiper and brake light work, the box was okay and doing what it is s'posed to.

I meant to grab one when I was getting salvaged harness cables, but forgot. Guess I'm heading back to the pick-it yard.

—Kel

 

[phattyduck]

The '99-'02 rear hatch houses the keyless entry receiver, which also controls all back door functions (and communicates to the body ECU via an early-style not-quite-CAN bus).

With the rear ECU unplugged, the main 4-doors should still lock when pressing the driver or passenger lock buttons, so I suspect there is still some issue up there.

The alarm will not activate if the body ECU does not receive the 'ok' signal from the position sensors on all 4 door locks and the rear hatch lock via the communication bus (nor will the single-beep activate on non-alarm trucks).

Since the rear window works from the dash button, the communication bus is working, so that's a plus. I'd track down possible issues in the driver's door harness and/or master switch panel. There may have been a related issue that happened up there at the same time.

-Charlie