Hi and thanks for using 2CarPros.com. I have to be honest, this is a tough call for me because of the conversion. When these vehicles are converted, many changes are made to the OEM wiring design and formats, which means I cannot review the original equipment wiring schematic to help determine the issue. However, I would like to make a recommendation to you which you may find beneficial. These vehicles have a wiring harness which is located between the door frame and the door. When you open the door, you will see it located in the front section between the door and the A-pillar. Often times, the wiring in at this point is damaged from opening and closing the door. What I would like you to do is inspect the wiring at that point. To me, it sounds like the power from the main switch in the door has a wire which has been damaged and is now making contact with the interior lighting system. Hence, when you try to use the locks, power is sent to the lights rather than the lock solenoids.
If possible, check that for me. Here are general directions for checking wiring and using a test light. If you do not have a test light, they are inexpensive and can be purchased at any parts store.
Again, not having the customized wiring schematics makes it more difficult, but we can still give it our best try.
Let me know what you find when you check.
Sunday, June 3rd, 2018 AT 4:24 PM