Door locks issue, need diagram

[Devin]

I have some annoying door lock issues. Currently I cannot actuate the door locks on the driver front, and passenger rear. I changed out the rear actuator and it still does not work. Tested it with my bench tester and the actuator functions. This got me thinking it was wiring. I need to look at a diagram, but I can't find an electrical diagram in my 1990 shop manual. Hopefully someone here can track one down, even if it is for a newer model...

The exact situation:

Driver Front: Not OK
Driver Rear: OK
Passenger Front: OK
Passenger Rear: Not OK
Driver lock switch: OK
Passenger lock switch: Not OK.

All the window motors are currently working, although I did have to swap the Pos and Neg on the passenger rear window motor harness because the donor motor polarity was apparently reversed.

I do have an issue with my keyless entry as I am not getting any power to the keypad. I swapped computers but did not seem to matter. Not sure if that could be connected or not.

 

[Texas Marauder]

 

[Devin]

@Texas Marauder bless your heart.

 

[Devin]

And now that I am looking at this, I can see that 118 and 117 run through the keyless entry. This'll be interesting to diagnose!

 

[Texas Marauder]

Keyless entry. Good luck. You'll need it.

 

[SHOrod]

With a multimeter or test light this should be pretty easy to test for the issue. Do you have a test light and/or multimeter? The hardest part will likely be gaining access to the switches, solenoids, and the keyless entry module, and probably the wires in the accordion boots between doors and the cabin. If I remember correctly from my time with my 1993 SHO, the keyless entry module is located in the trunk. You might try the passenger lock switch with the passenger door in various states of open and closed. Easiest would be to hold the switch in one position and keep it pressed while slowing opening or closing the passenger door. If you find a spot where the switch works, that pretty much guarantees that you have a broken wire in the according boot between the door and the cabin, making intermittent contact within the wire insulation. The same and be tried for the driver's door lock and, more challengingly (is that a word?) the keypad.

Since your driver's door lock switch seems to be working correctly as do some of the lock solenoids, it doesn't sound like the issue is likely to be with the RKE. You've bench tested the passenger rear lock solenoid and confirmed it works when it has good power and ground. So next steps would be to test for power and ground to the different components. A long, fused jumper wire and a test light or multimeter (or PowerProbe) will greatly help to troubleshoot. With the wiring diagrams above that should greatly help you confirm where you should have power and should have ground. You have probably already figured out that the RKE module determines lock and unlock via a ground signal to pins 10 and 11 respectively. You can also tell from the diagram that both lock switches are effectively in parallel, and same for the lock solenoids. So that confirms that, other than your keypad issue, the RKE is working.

If the attempt at slowing opening/closing the doors doesn't confirm anything, then you'll need to take some voltage measurements at components.

As for the keypad, does just the backlight not work, of does pressing 7/8 and 9/0 at the same time not lock the doors? If no light and no function, I'd be quite suspicious that the COM line is broken between the keypad and the RKE module. This would likely be broken in the accordion boot between the door and the cabin. From the provided diagrams, you know what color wire you're looking for.

For the door lock solenoids, get to the lock solenoids and monitor for power and ground to the solenoid when using the driver's switch to lock or unlock. If you can do this by back-probing and leaving the solenoid connected, that will be most telling since a poor connection can fool a high input impedance multimeter into appearing like there's good voltage, although there's not enough current flow to actuate the solenoid.

-Rod

 

[Devin]

Thanks @SHOrod for that comprehensive reply. Note, this isn't RKE, just KE. Not sure what the differences are. With that said, the number pad doesn't work at all. My original died (I thought) and I replaced it with a NOS unit, and it still doesn't work. Replaced the computer and nothing changed, so I'm thinking you are correct that a wire is broken somewhere along the line.

I do have a multimeter, I'm hoping to dig into this today.

 

[Irish Pride]

Check the main harness in the drivers door jamb, inside the rubber boot. Very common place for broken wires in the harness. I had all kinds of electrical issues in my blue 95 and that's where I found them. Had 3 or 4 broken/crimped wires.

-Chad

 

[luigisho]

I also had corroded contacts within the master switch on the driver door that made some functions inoperable. Once I cleaned the contacts and that worked, and the other I had to swap with another used good one.

 

[FastCAD]

Thanks @SHOrod for that comprehensive reply. Note, this isn't RKE, just KE. Not sure what the differences are. With that said, the number pad doesn't work at all. My original died (I thought) and I replaced it with a NOS unit, and it still doesn't work. Replaced the computer and nothing changed, so I'm thinking you are

Thanks @SHOrod for that comprehensive reply. Note, this isn't RKE, just KE. Not sure what the differences are. With that said, the number pad doesn't work at all. My original died (I thought) and I replaced it with a NOS unit, and it still doesn't work. Replaced the computer and nothing changed, so I'm thinking you are correct that a wire is broken somewhere along the line.

I do have a multimeter, I'm hoping to dig into this today.

And now that I am looking at this, I can see that 118 and 117 run through the

Thanks @SHOrod for that comprehensive reply. Note, this isn't RKE, just KE. Not sure what the differences are. With that said, the number pad doesn't work at all. My original died (I thought) and I replaced it with a NOS unit, and it still doesn't work. Replaced the computer and nothing changed, so I'm thinking you are correct that a wire is broken somewhere along the line.

I do have a multimeter, I'm hoping to dig into this today.

I did not catch the Gen of your SHO but I had a problem replacing my keypad in my '91 with a new keypad harness and it did not work but the original keypad worked fine all buttons and light but the button numbers somehow got erased. So I compared the wire harness of the new unit with the original. Everything was the same but the new unit had (two) black wires and my original had (two) black wires but (one) had a deliberate (clean) cut so I cut that black wire on the new unit and it is the working keypad currently in my SHO. This was a few years ago and I think the only new keypad I could get at the time was for a GenII. I hope this might help.
keyless entry. This'll be interesting to diagnose!

correct that a wire is broken somewhere along the line.

I do have a multimeter, I'm hoping to dig into this today.