So, who wants to know how to swap in digital climate control?
Letís start off with what youíll need.
Blower Assembly (87130‑20650)
Blower Controller/Resistor (87165‑41010)*
Fresh/Recirculate Servo (87106‑20440)
Mode Servo (87106‑20410)*
Air Temp Servo (87106‑20430)
Temperature damper lever
Interior Temp Sensor (88790‑12020)*
Exterior Temp Sensor (88625‑20500)
After-Evaporator Temp Sensor (88625-20510)*
Solar Sensor (88625‑47031)*
*=Available in USA as a Toyota/Lexus part
For visual reference, here's some parts:
Now, first step is to remove the manual components. Iíll start by assuming you can remove the glove box, radio bezel, and the radio itself as shown below.
First, we turn our attention to the blower motor. Unplug the resistor and power supply plug for the fan, then unbolt the blower motor (2 nuts, 2 bolts) and wiggle it out, making sure to slip the cable off of the damper mechanism.
Then, we go to the driverís side and look up by the pedals. Youíll see two distinct mechanisms here, the upper one is for mode control and the lower is for temperature control.
Slip the control cables off of the levers and pop them out of their retainers. Pop the short linkage out of the mode control, then you can unscrew the remaining bit of the lever, but donít remove the big white round plastic bit. Move down to the temperature control and remove the screw holding on the lower lever, then remove the lever itself. Now, you need to swap the remaining lever for the climate control one. Just wiggle it until it pops out, then pop the other one in.
Now go back the the manual controls so you can remove them. Depress a tab on each side of the dash controls and slide it out of the dashboard. Disconnect the harness from the controls and then you can pull them completely out.
Now grab the harness and start unplugging, there will be a blue plug and two that go into the BCM/fuse box, plus one on the side by the blower motor for a thermistor. Pull the harness out and set it aside for now.
Now its time to start installing the climate control components. If you were wondering, Toyota is lazy, so the mounts for the motors are on the components already present in you car (except the blower motor). Mount the motors and shown in the picture below (there is one mount missing for the temperature motor, but the ones that are there are sufficient). On vehicles with ABS, it helps you install the screws if you unbolt the ABS computer.
Now install the new blower motor assembly with the damper motor on it, installation is the reverse of removal. Note the picture below for how the damper motor is mounted, the mounts are not present on the manual assembly.
Now itís time to tackle the wiring harness. If you just install it as is everything will work, but you will have one problem: no A/C. To fix this we need to do a little wiring work to get the after evaporator temperature sensor wired up. Take the manual A/C harness and grab the blue plug, we need the green-yellow and green-red wires out of it. You can see them pictured below.
Use a small flat head screwdriver to pop up the plastic tab on the plug, the, use it to lift up the retaining clip inside the plug holding the pin in, now you can slide the pin out. Once both of them are out, grab the small white plug on the harness and pull, the wires should slide out of the rest of the harness. Pop the plastic tab up on the climate control harness and slide the pins into the same spots on the new connector. The wiring harness is now ready to go.
You will need to install a second temperature sensor after the evaporator otherwise your A/C will, at best, only work on "max cold" mode. This is fairly simple, just follow the wire for the one already in your car, pull out the white plastic rod it sits on and secure it alongside the preexisting one, then stick it back in.
To install the harness, plug the matching connectors into where you unplugged the old ones, take note to plug in both evaporator temp sensors. You will have two separate groups of connectors left (plus one for the cabin temp sensor), one side goes to the blower motor (the one with the large black plug), and the other goes to the two motors. The blower motor should be fairly obvious, plug in the fan controller/resistor and fan, then snake the damper motorís plug up the side of the blower motor assembly and plug it in. On the motor side, the plug with the longer wires goes to the mode motor, and the shorter one goes to the temperature motor.
Now for the temperature sensors. For the interior one locate the vent on the lower part of the dashboard, on the other side of the dash there will be an unused mounting point for the sensor. Just line everything up and tighten it down with a screw, then plug in the connector. The exterior temp sensor is a bit of a pain, but you need it for proper system operation. This one is more up to the preference of the installer, I chose to mount mine in the wheel well by the fog light, but the important part is that the wires from it must tap the yellow-green and yellow-black wires on the notorious blue plug.
The system also needs a solar sensor for proper operation, but the stock one is different than the one needed for this conversion. The new one is a little bit smaller and I chose to drill a hole for it in the bottom of my A pillar plastic to keep the auto on headlights. The little thing looks like this:
Wiring for this is pretty simple, but I had to figure out the pinouts on the harness before I could figure out which wires are for it. The signal for the solar sensor goes through the blue plug on two wires, one white and the other white-blue, on the bottom of the plug near where the swapped wires go. The plug for the solar sensor is the same one as for the evap temp sensor (90980-11918, plus two wiring pigtails), just run the wires to those mentioned above and plug the new sensor in wherever you want to put it.
Now youíre ready to go, just swap the panels on the radio bezel (two screws, then slide the panel over), reassemble everything, plug the controls in, and enjoy.
-The hardest part about the install is getting all of the parts (special thanks to all those that helped me). The blower motor assembly is next to impossible to find, and the plastic bits (mode linkage and the temp damper lever) for the motors are hard to find on their own. The best way to get the parts is to find a buddy in Europe who is parting out a Celica.
-The exterior temperature sensor, like the parts above, can be hard to get, especially with the wiring harness connector with pigtails. I suspect that an exterior temp sensor from any similar year of Toyota/Lexus will be compatible.
-The temperatures will be in Celsius, time to join the rest of the world.
-Observers will note that there are some leftover wires on the blue plug that don't connect to anything, however, it would seem that they don't need to as I haven't had any error codes pop up.
-You've got 5 speeds for the blower now.
-Edited on July 12, 2012 to add steps omitted from the original guide.