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SERVO SUB-ASSY, DAMPER, Genuine Toyota 87106-35040


Well-Known Member
Feb 11, 2016
Country Flag
So, I know this little black box as a 'temperature control unit', at least that is what I call it. In the 6 or so years that I have owned my Toyota, it has never worked. This means that to adjust the cabin temperature, I’ve had to manipulate the wire cable that attaches to the arm on the servo sub-assembly at the bottom end (in the passenger footwell side) back up to the control valve in the engine bay just behind the intercooler, by hand. This has been quite a pain in the proverbial.

Anyway, I had read someone’s write up somewhere that this problem could be sorted out by removing the servo sub-assembly, opening up the unit, and simply turning the plastic cog that drives the arm as this tends to wear out on the one side that meshes with the teeth from the cog driven by the motor. The difficulty lies with the fact that actually getting a screwdriver small enough to get in there to remove the three retaining screws that hold the servo to the pressed metal frame is rather a challenging task, especially with half one’s body hanging outside the vehicle whilst trying to contort oneself enough to get to grips with the screws.

The good news is that it can be done, and I am very happy to have finally go to grips with this niggling issue. I can now readily adjust the cabin temperature at will. Happy days.

Top tip: make sure that the arm that controls the cable is set in the cold position before removal. This is so that you know the correct position of the internal cog before you remove it to turn it to the 'un-used' side.

This was the offending unit:

To help gain access to the top of the unit and remove the three screws that hold the black plastic box to the steel frame, undo two of the three screws that hold the unit to the underside. This will allow one to gently pull the unit down enough to undo the three retaining screws.

Unfortunately, I lost some of the phots in-between. But essentially, once the unit can be gently pulled down, undo the nut that holds the arm to the top of the unit and remove the arm (I did this by prying it off with a flat head screwdriver), then I used a posi-drive screw head held in a spanner to undo the retaining screws. The case can be easily opened by releasing the clips around the edge of the unit, but do this carefully, they are very fragile (yes, I broke one). Remove the small internal circuit board, no wires to worry about, to get to the main cog. Take a photo of it before you move it. Then, simply lift the cog and turn it 180° and re-insert it. Reassemble in reverse order.

The offending cog with worn teeth.

Top Tip: Before reconnecting the control wire to the unit, ensure that the control valve in the engine bay (at the other end of the control wire!) can move freely. Spray it with some lubrication and move it back and forth to make sure it is not stiff, or you will likely wear the teeth out on the cog again, and you only have one chance to do this.