Rear Door Electric Lock Install (pre 1998)
by Chris Velardi
Updated February 4, 2014
Hummer wagons prior to 1998 had a simple key lock on the pair of rear doors which owners call barn doors.This means you have to carry another key to open the rear doors. On newer trucks the barn door lock is wired to the electric door locks in the rest of the truck. The following is a way to retrofit your older Hummer wagon so the doors open with an electric actuator.
Getting the right parts and tools before you start:
I used Painless wiring's "Jamb Tac/ Three contact (you only need the 2 contact but the third can be used for future stuff) wireless connectors. Purchased from Jegs www.jegs.com for: $17.99
2- Fifteen-foot rolls of 14 gauge wire. I used blue and green like the door actuator, or you can get pink and black like the Hummer already has. Purchased at the local auto parts store for: $5.95
1- Tesor 2-wire door actuator purchased for: $4.50+ shipping.
1- Remote (if you don't have one already) from Rostra (who manufactures the receiver for Hummer) part # RT1 (one button) www.rostra.com for: $35.
Tools that you will need:
- Cordless drill
- Soldering Gun
- Ratcheting Bit screwdriver
- ½" Drill Bit
- 2- Butt End Connectors
- ¼" Nut Driver
- 7/64" Drill Bit
- Wire Strippers
- #2 Philips Head Bit
- Electrical Solder
- Razor Knife
- Fine Tooth Metal Jigsaw Blade
- #1 Fine Philips Screwdriver
- 7/8" Wrench
- Electrical Tape
- Dielectric Grease
- Center Punch
- Digital Multimeter
- 2- Nuts to Match Door Handle Bolts
First I took the passenger rear door panel off and found the stock actuator pink and black wires used on the front 4 doors. I spliced off the wiring before it goes into the door in the doorjamb (between the front and rear seats). Too making sure I had the right wires I put the multi meter on buzz tone and pierced the wires (nothing worse than soldering a splice into the wrong wire).
My favorite way to splice a new wire into an existing one, is to cut away a ½" of insulation on the original wire where you want the wires to be joined, then separate the strands in the center of the cut to create two equal groups of strands. (A toothpick or similar fine pointed instrument will work well) Then strip 5/16" of insulation off the end of the new wire. Insert the new wire in-between the 2 strands of the original wire and twist them together and solder (making sure to heat from the bottom and apply solder from the top so heat has to travel all the way though the wire to suck the solder all the way through, and you don't get a "cold " solder joint. Then tape up the bare spots in the wires with a good electrical tape (like 3M).
At this point I spooled out the two strands of 14 gauge wire and taped them together to make a custom wire loom and routed them behind the floor/ kick panel molding, behind the rear seat, under the carpeted floor board (in a recessed channel) and up into the rear barn door jam.
I located the wireless door jam contacts so they would not interfere with any of the door hinge bolts. (I should have taken more time to make them more centered and perpendicular in the hinge, but I didn't and mine are not the most attractive). Each of the wireless connectors have about an 1/8" deep mounting surface. There is only about 3/16' gap available between the hinge surfaces when the doors are closed, so I unbolted all the bolts that mount the door to the hinge and removed enough of the hinge so the entire surface of the wireless jam contact was flush with the hinge (only necessary to do this on one side of the hinge, it is easiest to make the cut out on the door side of the hinge and I used a jig saw. There are good instructions on the painless wiring Jam Tac on how to install them, locating the matching contact on the opposing hinge is made easy with a dab or grease on the contacts of the first one you mount, and close the door. Using a good center punch (or a sharpened concrete nail) to start your drill hole (use an 1/8) pilot hole before trying to drill out the hole with the ½ wide bit.
Now it's time for door work. First take the window frame off with the ¼" nut driver in a cordless drill (makes the job effortless). Then take the 4 door handle screws off, and the 14 Philips heads screws off that hold the inside door panel on. At this point the door is free to work on, I took some extra nuts I had, and secured the door handle onto the door to find the best angle to mount the actuator.
I removed the old key cylinder and cam, since it was frozen solid with corrosion. Then I replaced it, just to fill the hole, but did not put a cam on it. On the locking mechanism there is a round cam with 2 open holes and one steel dowel in the third. I found no matter where I positioned the actuator the dowel would interfere with the ability of the actuator to lock and unlock. So I used a punch to remove it. Now I was able to make one nice smooth action back and forth without binding to make the cam do it's job (prevent or enable the handle movement or lock and unlock).
After finding the correct free movement angle and a distance that would allow for adjustment, I outlined the actuator's body with a black "Sharpie". This is the most critical part of the job, if the actuator is mounted improperly it will not work 100% of the time or if it's movement is obstructed or hindered it will probably burn out. I literally held the actuator at any and every possible mounting location and angle to find the smoothest movement of the cam.
The Tesor actuator comes with a coat hanger thickness rod with a 90-degree angle bend with a mushroom end that allows smooth free movement and travel inside the nylon actuator's pivot hole. This works so well that I used a second one to connect it to the cam, (because the cams hole was larger than the actuator's and the head of the rod could pull or fall out it, I put a small washer on the end of the rod. This keeps the rotation of the cam bind free).
Although the original key and inside locking lever can move 180 degrees to lock the door, the electric actuator can only give you 90 degrees of movement when it is attached to the outside of the round cam. Luckily this is all the mechanism needs to work. Finding these limits and the proper working angles takes some time. I forced the actuator (by hand) with the linkage attached to work, unlock, lock, unlock, lock a few dozen times, watching the cam and feeling the movement for the best position.
The Tesor actuator also came with a small device that can attach two small rods together and this is what I used to create the proper length and throw. Once I was sure this was the best location I held the actuator down and drilled a pilot hole (using the mounting holes as a template and guide.) Now I grabbed a spare 12-volt battery and tested it (all good!). With this done I flipped the door over and screwed it into place. (Luckily the factory carpet will cover the two small round head screws.) With this in place I aligned the door panel on the door to see how much of the 2" pink hard foam insulation I would have to cut out to clear the new actuator. A quick mark or two with the Sharpie and few cuts with the razor knife and the area was clear.
Now I was able to estimate the length if wire I would need from the actuator to the door jam contacts. (I added a little extra wire to make it easier to maneuver it into place). I use dielectric grease on all the connections that were not soldered. Now with and extra set of hands line the door panel up with handle and the mounting screws. Set the 4 handle retaining screws first, then put in 3 or 4 of the door panel to hold it to the door. Once this is done, test the handle to make sure it has been lined up properly (both paddle handles should activate the mechanism) then put the rest of the screws in the door panel, and put back in the window frame. Then test the remote (making sure the door is closed, remembering that they are "wireless" Jam Connectors, if the door is open the lock will not work) At this point you just want to make sure the inside door locking lever is in the lock or unlock position that the other 4 doors are in (or you will be unlocking one while the others are locking)