I don’t really know where to go with this diagnostic, so let me begin at the beginning. One day I went to get into my truck and the doors were locked, for apparently no reason because I had to the best of my knowledge not locked them. I got my fob out of my pocket and hit the unlock button. The interior lights came on but the driver door did not unlock. I hit the unlock button again, which in theory should have unlocked all the doors, they did not unlock. So I used the key to unlock the driver door and tried using the unlock button, again the doors didn’t unlock. And so begins the diagnostic.(If you want to know the solution without looking at the details of the diagnostic Skip to the section marked Edit, you won’t believe what the actual problem turned out to be)

I went straight to the fuse boxes and checked all the fuses associated with doors and locks. All are good. At this point I knew I was going to have to go deeper. I then went to the prescribed diagnostic procedure for: Doors do not lock/unlock using the remote transmitter. A1 simply verifies that the locks either do or do not work with the remote transmitter. And of course they do not.

Next step is A17 Monitor the RAP (RAP module) PID DD_Lock. Did the PID DD_Lock indicate short? Yes it did.
Next step A18 Measure the voltage between RAP module C 257-11, Circuit 120 (PK/LG) and between RAP module C257-22, Circuit 119 (PK/Y) and ground. Is voltage indicated? Yes on both Circuits.

This is where the diagnostic falls down. I verified that the power was on the two Circuits to the RAP module but not coming from the RAP module. So doing my best to be diligent I started taking door panels off to check the switches. No problems found with the switches, yet at both switches, there was power on both C 119 and C 120. Somehow obviously there is a short to power on these 2 circuits. I pulled the wire boots from both doors looking for someplace that these two circuits might have gone short to power but came up empty. I looked in all the places that are possibly accessible including the relay panel under the right cowl cover. While doing so I verified all the relays, the driver unlock relay, the all unlock relay and the all lock relay. All are good, and I found no short underneath the relay block. I can find no place that is accessible where there might possibly be a short to power.

A few anomalies that I found were these. When testing the 2 circuits with a test light to ground I can hear and feel the relays trip, I also notice the relays trip using the door lock or unlock buttons. Another is that when using the key fob the interior lights and the horn chirp work as expected with the proper press of the proper button. Which in my mind tells me the power to these two circuits is isolated within a closed system and testing the circuits to ground is trying to activate the relays but can’t because both sides, lock and unlock are shorted to power. And lastly, when entering a door unlock code on the door key pad, the interior lights also work as expected.

My conclusion has come to be that there is a short someplace in the Generic Electronic Module or GEM, but I find no information anywhere that either Ford or Lincoln publishes which supports my conclusion. The only thing to this point to possibly support this conclusion is that in the trouble shooter section of my Solus Edge, it does list this as a possible problem calling it an SJB (smart junction box)

I have been an ASE Certified master and was in the business for 30 plus years (now Simi-retired and no longer making a living working on cars and trucks). Because I am up in years (just like my truck) and with a bad back now to boot, I don’t feel I can press myself into the confined space needed to replace the GEM on my truck. It is located on top of the interior fuse block and for that reason I will need to have the local stealership put the GEM in for me if that is indeed where I need to go. Don’t get me wrong, ASE Certified master, yes. Did I work for the Dealerships, only in my early years before I saw all the stunts that get pulled on customers; I spend the last 26 years of my career as an independently employed Tech.

I have never run afoul on a diagnostic like this before and I do trust my instincts when it comes to electrical systems, but I was wondering if there is anyone who might be able to help me verify my diagnosis or if anyone else has had a similar problem that would help confirm the diagnosis before I take it to the Dealer, who by the way won’t give me a good estimate, just a possible ballpark figure, which isn’t pretty.

EDIT:

I did go ahead and replace the GEM module and to my shock and horror it was not the problem. Once I got past the shock of the GEM module not being the problem, I returned to the basics of what I knew to be true. It reminded me of the quote from Leonard Nimoy,” When you eliminate the impossible, whatever remains, however improbable, must be the truth” I literally had to approach the problem this way.

What could cause a short to power on two independent circuits that run the door locks? To be honest I didn’t have a clue. I knew it wasn’t the switches, it wasn’t the rap module, it wasn’t any of the relays in the system, or the wires that controlled them. And now I knew it wasn’t or at least I thought it wasn’t the GEM module. And at this moment I can’t give good cause or reason for with any of what I am about to reveal.

When I did everything I knew, had checked every circuit (except one). The actual circuits to the door lock actuators. But how to do that without having feedback from the shorted to power circuits 119 and 120. Disconnect the wires from the actuator and test the actuator independent of the actual circuit. I tested first the wires to the actuators; no power was present on either side when checked to ground. And no power on the wires when trying to either use the button switch or the fob.

Then I tested the actuators themselves Guess what, no operation. Not just on one, (I tested the driver door first) but all 5 actuators were bad. All open and all at exactly the same time. What are the odds, beyond the odds what was the cause?

I don’t have a real good answer for that question, but it is true that all 5 door lock actuators were fried and all at the very same time. I can’t, now that I think about it, even come up with a good theory to explain how it might be possible. I replaced all the actuators and now the locks work fine. This is almost one for the believe it or not show