The tailgate open warning light is on permanently

If the actuator works the problem could be the power supply to it. A common fault is the wiring loom. With the tailgate wide open lookup between the tailgate and body where the hinges are. Off to one side there will be a dark coloured rubber or plastic tube across the gap. This is the wiring to the lights and features in the tailgate. Over time this can get worn and the wires can wear and snap. A good auto electrician can fix this for you.

Neil. Tailgate lock actuator may be wearing out. Tail gate lock actuator replacement links below. Check the attached links,instruction and guides, Good luck
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LIFTGATE HARDWARE PART 2 LOCK DETAIL for Buick Rainier
Door Lock Actuator 1ADLA00004

The lock actuator motor is most likely sticking due to corrosion, open up the tailgate and replace the electric power lock actuator motor. If you need instructions on how to access the inside parts you can get them here for small subscription fee.

Annoying, but easy to fix: Actuate the opening handle and manually rotate the latch to the open position.

1. Remove third panel, open tailgate, observe the five torx bolts.

2. Remove the two outer torx bolts.

3. Close tailgate, remove handle bezel. The bottom is held on with two plastic "Fir tree" pins.

4. Open taligate, remove the three remaining torx bolts, close tailgate.

5. Observe that there are two plastic ScotchLock type items that hold the latch actuator rods. Color the exposed threads with a Sharpie for ease of re-assembly.

6. Open the two plastic actuator rod holders and remove the handle assembly.

7. Install the new part and secure the three bolts.

8. Install the actuator rods in the clips, leaving the previously exposed threads, ummm, exposed.

9. Verify proper operation of latches with the third panel installed.

10. Install bezel and two retaining bolts.

Here's another version of replacing it that another guy modified from the above instructions....

I broke the back latch on mine and had to change it. A couple of changes I would make to the instructions are:

1. forget about the third panel, whatever that is, unless it's another way of saying "tailgate"

2. unsscrew the two outer bolts on the inside of the tailgate and close tailgate.

3. pull off plastic cover, bottom fasteners like said above are "pine trees", just pull straight out

4. the actuator rods are just snapped in, BEFORE doing anything else, mark the edge of the fastener, and more importantly

5. TIE a string, or use a long piece of tape on each rod so that when you undo the fasters for the rods, the rods don't fall down to the bottom of the tailgate. I actually used alligator clips off a multitester as they were handy, but you get the idea.

6. loosen the three bolts holding the handle in (don't remove them, so it doesn't torque over when you start in on the last), when all are loose, remove the three bolts, and disconnect the actuator clips. I could do this with my fingers, and it helped to have the bolts out so you could wiggle it a bit for a better grip.

7. you can now remove the handle by rotating it clockwise and pulling outward a bit on the tight spots of the tailgate.

8. intstall by working backwards up this list, the only other thing is for the right actuator rod, I held it with a needle nose pliers to get it into position.

Hope this helps, and it's not really a bad job.

Tailgate latch, handle and lock

• Open the tailgate.
• Remove the two bolts and detach the door stop.
• Lower the tailgate and remove the tailgate access cover.
• Disconnect the control rods.
• Detach the retaining nuts and remove the handle and lock cylinder assembly from the tailgate.

...
Door trim panels

• Disconnect the cable(s) from the negative battery terminal(s).
• On manual window equipped models, pull the window crank cover aside, remove the screw and detach the handle.
• On the front door of power window equipped models Pry up on the retaining clip at the front edge of the armrest and lift the armrest switch control plate out and disconnect the electrical connections,then remove the retaining bolt from the opening.
• Use a small screwdriver to pry off the courtesy light cover for access to the trim panel retaining bolt.
• Carefully pry off the mirror trim panel from above the front edge of the door panel.
• Once all of the bolts are removed, remove the trim panel by gently pullingit up and out .Detach the courtesy light bulb housing from the panel.
• For access to the inner door components, remove the speaker (if it would interfere with watershield removal) and the screws from the trim piece at the lower trailing corner of the door, then carefully peel the watershield from the door.
• Remove the screws securing the latch.
• Working through the large access hole, position the latch as necessary to disconnect the electrical connector and disengage the outside door handle and outside lock cylinder to latch rods and the inside handle-to-Iatch cable.
• Detach the locking rods by unsnapping The remaining outside handle retaining nut can be reached through the access hole in the door frame and the upper striker the portionof the plastic clip engaging the connecting rod, then pulling the rod out of its locating hole.
• Position the latch as necessary to disengage the door lock actuator hook. Detach the cable cover and disconnect the cable from the latch. Remove the latch assembly from the door.

· Open the tailgate and remove the tailgate liner.
· Remove the ten bolts(5) that secure the tailgate cover(4) to the inside of the tailgate and remove the cover.
· Using a pencil,mark the actuator rod(3) at the control(2) for the latch(1) being serviced.
· Disconnect the actuator rod from the control
· Remove the two bolts(7 and 8) that secure the latch(5) to the tailgate(4) and position the tailgate check cable(6) out of the way.
· Remove the latch and actuator rod from the tailgate as an assembly.
· If required,remove the actuator rod from the latch.
You will have to remove the tailgate cover. The cover will most likely be held on by some of the tailgate metal access cover.

Ignition Lock Cylinder REMOVAL & INSTALLATION With Key

1. Disconnect the battery ground.
2. On tilt columns, remove the upper extension shroud by unsnapping the shroud from the retaining clip at the 9 o'clock position.
3. Remove the trim shroud halves.
4. Unplug the wire connector at the key warning switch.
5. Place the shift lever in PARK and turn the key to ON .
6. Place a 1⁄8 in. (3mm) wire pin in the hole in the casting surrounding the lock cylinder and depress the retaining pin while pulling out on the cylinder.
7. When installing the cylinder, turn the lock cylinder to the RUN position and depress the retaining pin, then insert the lock cylinder into its housing in the flange casting. Assure that the cylinder is fully seated and aligned in the interlocking washer before turning the key to the OFF position. This will allow the cylinder retaining pin to extend into the cylinder cast housing hole.
8. The remainder of installation is the reverse of removal.

Non-Functioning Cylinder or No Key Available FIXED COLUMNS

1. Disconnect the battery ground.
2. Remove the steering wheel.
3. Remove the turn signal lever.
4. Remove the column trim shrouds.
5. Unbolt the steering column and lower it carefully.
6. Remove the ignition switch and warning buzzer and pin the switch in the LOCK position.
7. Remove the turn signal switch.
8. Remove the snapring and T-bolt nuts that retain the flange casting to the column outer tube.
9. Remove the flange casting, upper shaft bearing, lock cylinder, ignition switch actuator and the actuator rod by pulling the entire assembly over the end of the steering column shaft.
10. Remove the lock actuator insert, the T-bolts and the automatic transmission indicator insert, or, with manual transmissions, the key release lever.
11. Upon reassembly, the following parts must be replaced with new parts:
    • Flange
    • Lock cylinder assembly
    • Steering column lock gear
    • Steering column lock bearing
    • Steering column upper bearing retainer
    • Lock actuator assembly
12. Assembly is a reversal of the disassembly procedure. It is best to install a new upper bearing. Check that the truck starts only in PARK and NEUTRAL.

It is the rear door lock actuator. It controls the window and hatch lock. Unfortunately the actruator is a dealer item and Ford does not sell the actuator by itself. You have to putchase the entire latch assembly whic comes with the actuator. It will run you about $150 for parts.

is yiur batery in your key ok?