jimmy283

If the passenger doors are manually locked and the gear shift is moved from drive to park, all the passenger doors unlock. Moving the gear shift back to Drive will only lock the driver door. Checked the lock relay and it works properly. Found the lock fuse had blown. Changed the 15 amp "lock" fuse and had it blow again when the driver door switch commanded lock to all doors. Only the driver door went to lock. Passenger doors were unlocked and the "lock" fuse was blown.

Am trying to duplicate the driver door switch with the pictured above harness plug removed from the door switch. Giving voltage to the light blue wire ( third from the right end) and the white wire on the opposite side will lock and unlock the driver door. Applying voltage to any of the other pins does not command any action with the engine off. With the driver door open for quite a while and the engine off, I lost voltage on the second yellow wire from the end---is the PCM doing something here?

My reason to test the harness plug when removed from the door switch was to try and confirm the door switch was either good or bad. However it seems my approach will not work because with the engine running, there are multiple wires with voltage that did not have voltage with the engine off. This must not be a simple rocker switch. Is there a way to test the harness plug wiring by duplicating the door switch to determine if the door switch module is defective?

a55bruce

The door switches and the BCM are controlling the relays that lock/unlock the doors. The door switches are OK if they are clicking the relays. The drivers door lock does not get its power from the LOCK fuse. That's why the drivers door is working even if the fuse is blown.
If the unlock works but the lock command causes the LOCK fuse to blow I suspect you have a short in the wiring somewhere.
Pull the lock & unlock relays out, remove the lock & unlock fuses. Check for continuity from the fuse plugs to ground.
My shorted wire idea gets confirmed if you find any continuity to ground.
Good luck, let us know what you find.

jimmy283

a55bruce--thanks for this information.
Yes, I'm getting some continuity. I had 100+ ohms on the lock fuse---separated some suspicious wires on the barn doors and reduced the lock fuse terminals to open.

Still get 2 ohms on the unlock fuse terminal closest to the driver with the dome lights off and the harness plug installed in the driver module. This value increases to 45 ohms with the dome lights on.

Removing the plug, the lights off value is 1.9 ohms and the lights on is 43-44 ohms. The other three terminals on the fuses are open.

a55bruce

GREAT! that sounds like you found the problem.

Weird. Are these readings with the UNLOCK relay removed? If yes, check that terminal with the voltmeter. Stray voltages on the continuity test will give weird results.
Maybe you have some more suspicious wires somewhere.
Do you have 2 or 3 door relays on that fuse block? If 3, remove all 3, try again.

jimmy283

a55bruce--
Yes--readings with the unlock relay removed. Terminal has less than 0.1 volt.

I have three door relays on the fuse block--the third is for the keyless entry option. All three relays removed. Now--the resistance on the unlock fuse moved from the terminal closest to the driver to the opposite terminal-- the terminal closest to driver is now at open and the other unlock fuse terminal at 98 ohms with the dome light off and 144 ohms with the dome lights on. This is with the harnesses connected at the driver door module.

I repeated this by reinstalling the keyless entry relay and got 2 ohms on the unlock fuse terminal closest to driver and open on the other fuse terminal just as previous. So it appears that the above paragraph with all relays removed has the unlock fuse terminal away from the driver as the suspect wiring. Do you know the routing of the wire on that side of the fuse?

a55bruce

Jim,
The readings should be "open" with the relays out.
Puzzling !
Did you try plugging everything back together & testing the lock function after you found the short at the cargo doors?
Here's the schematic to help you with the tracing of the suspect wiring.
http://www.revbase.com/BBBMotor/Wd/DownloadPdf?id=73915
Unplugging the door lock actuators may help sort out which door has the bad wiring.

jimmy283

a55bruce,
It has been raining heavily, the vehicle has been outside, and I am getting a water drip onto the emergency brake pedal extension. I imagine water has infiltrated wiring/contacts above this location and would explain the random ohm values. I say this although there is not any evidence of water in the side fuse compartment.

Nest step is to re-set the windshield.

a55bruce

When you get a chance, check the backside of the fuse block for corrosion & wet connections.

jimmy283

a55bruce,
No apparent wetness or corrosion.

Yesterday was a warm day and I observed the ohm readings on the fuses increase to open. Connected all relays and fuses and all was well last night. This morn, had several lock and unlock commands as I drove from place to place and then a lock command blew the lock fuse. No rain at this time.

I removed both connections to the actuator of the LR door and all other doors worked well with a new lock fuse. Working from your wiring diagram, I reconnected the unlock connection shown on the wiring as tan/black thinking I would eliminate the lock side which is blue with white stripe/black (your wiring shows this as gry/blk). The result is the lock and unlock functions on this door and all other doors all work properly with the top connection (blue-white stripe/blk) removed from the solenoid.

Your wiring diagram is invaluable but I am lost as to why the fuse opened this morning and why the actuator will work with one connection removed. Does the actuator solenoid have two windings--each pulling in opposite directions?

a55bruce

Great! You did pull up you floor mat to let it dry-out underneath before the rust starts? (suggestion)
WTF, How is this possible??? With one wire OFF of the actuator that door should NOT be functioning at all.
The wire you removed, 3-colors, blue-white-black????
If it has an internal short it could work in ONE direction but not both. The internal short would explain the fuse blowing on the LOCK command.
Nope, One winding. The relays reverse the polarity to the windings to reverse the direction.
Why the LR door? Did you have a reason to unplug that actuator?
Do the wire colors match up on the other doors?
The LR actuator does sound suspect, a continuity check from the unplugged connections to its case will confirm. Compare the readings with the other doors.