HeaterTreater installation on a RHD Vehicle

Thank you, Thank you, Thank you to John Rutter in the UK for providing the pictures and commentary. Hope UK customers already know what a windscreen and grub screw are. I’m not sure.

Just to set the scene - Heater-Treater repair work is done behind the glove box, being on the left side of my RHD Jeep


Glove box shape, on right-hand-drive Jeep Grand Cherokee


Heater-treater guide recommends you remove and dispose of this. I don't agree, it gives some damping when opening the glove box, so I'm keeping mine. Still need to disconnect it to drop down the glove box for access though


With the glove box opened, this is the motor that controls one of the blend doors for the heater/air-con mix. Another one sits on the other side of the heater box, inaccessible unless you remove the whole dash.


With the motor removed, this shows the side of the heater air box, which needs to be cut away for access to the blend doors within it.


Heater-Treater instructions have a diagram showing where to cut out the panel on a left-hand-drive car; mine is right-hand-drive, but the layout appears to be almost a mirror image.


Roughly-drawn lines on the plastic panel should be enough in this case, as a reminder of where I am going to cut into the heater air-box. Using the Dremel-type tool supplied with the heater-treater kit, fitted to a borrowed Black & Decker 'Wizard' mini drill (thanks Peter).

Had also used some wide masking tape to catch some of the swarf and rubbish that will result from the cutting process.


Having cut half-way, made a check before cutting closer to the air-con panel.


Messy, cutting/drilling the plastic panels.


This is the part cut out from the side of the heater air-box, on rhd Jeep. No cutting needed on bottom as that is slotted over the lower piece.

RHD 10

Similar cutting required to remove the inner dividing panel between the driver/passenger sections of the heater air-box. Cuts made here, section ready to be removed. Air-con matrix is to the left of the picture.

RHD 11

This is the smaller piece cut out from the dividing panel, on rhd Jeep

RHD 12

Having cut out side and inner sections, this shot shows the two heater blend doors (covered in plastic swarf) in the 'down' position.

RHD 13

Removal of the black plastic drive connector from this end of the blend door axle allows the doors to be lifted out for replacement.

RHD 14

View inside of heater air-box, with blend doors removed (heater below).

RHD 15

Compare the heater-treater blend doors as reassembled here for RHD installation, with the instructions showing LHD setup. Straightforward swap-over of the doors, ensuring slot cutout is towards the centre with the grub screws facing up and the control arm on the right.

RHD 16

Inserting the front-most replacement blend door, with allen key already in-place in the grub screw, to make it easier to tighten up when aligned on the axle shaft.

RHD 17

Both doors laid in place in the heater air-box, before inserting the spacer and driveshaft.

RHD 18

Spacer and axle now inserted through the heater-treater blend doors, ready for tightening in the correct position.

RHD 19

Driveshaft/axle positioned against the plastic stop, maximum anti-clockwise travel, blend doors in downward position.

RHD 20

Using the allen key to tighten the grub screws on each blend door, with the axle in the correct position.

RHD 21

Just checking that the blend doors move freely between up and down positions, verifying that the axle stop is in the correct orientation.

Note that with this kit, both doors now move under the control of a single motor. I chose not to pay extra for a two-motor, double-axle kit as that also entails cutting the glove box a small amount; this kit works well enough in single-control mode.

RHD 22

Not the tidiest result, with metal tape covering the cuts in the air-box panel, but it all goes back nicely enough, motor screw mounts onto the panel, metal clip replaced.

And it's all hidden behind the glovebox, so not visible otherwise.

RHD 23

RHD 24

Spent some time fitting the heater-treater to repair the heat/aircon blend doors on my Jeep Grand Cherokee today. That's me peering at the panel behind the glovebox before cutting into it (hence the Uvex safety goggles).

Job completed; can now heat the car and defrost the screen nice and quick, like it used to do.

Additional Photos of RHD Plenum Box Cuts

Front Cut

Interior Cut

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