I purchased a new servo from the dealership after trying to clean contacts on the inside of the old one did not work. The new one does not work either. I made a jumper and powered the motor off the battery and it works. I held the arm with my finger it has a lot of power( be careful doing this it has a lot of torque).

When I push the Mode button, the info screen shows the arrows move each time you push the button. Also both servos do NOT make any noise.

I am beginning to think it might be the mode button on the control.

I've read a lot but don't have a solution.

Any suggestions before I pull the control unit?

Bax

 

Servo motor should move and stop at various positions based on input voltage. Service manual would have voltage for each position of mode switch and based on that there would be certain position of the arm.

Salim

 

Thanks Salim. I saw the service manual some where on here. Time to trouble shoot.

Any one got a link to the service manual?

Bax

 

I'm still chasing this servo problem. i had a friend who's job is troubleshoot PC boards and integrated circuit boards on industrial systems come over and help out. I found a electrical diagram to help.
We determined that the servo is not getting a signal or voltage, so he's thinking the unit is not sending a signal to the servo.

So today I got a control unit from a salvage yard and the new servo still does not work. Everything works except, the mode(vent, defrost, floor).

Both servos have the same plug, air mix and air mode. So we switched plugs and both servos work plugged in the the air mix connector.

So I'm back to square one.
Check continuity in the connector and unit plug?
Does the mode work independent form air mix?
Suggestions?

Update:
I stopped by the Toyota dealers ship today a spoke with a very knowledgeable tech. The tech was telling me the same thing as my friend,no signal to the servo. He also gave some good advise for trouble shooting. I've been reading the repair manual and talking to the tech.

This is how the signal travels:

Button -> A\C ECU ->servo

So here's the good part. the A\C ECU is located behind the instrument cluster. I'm pulling that out to check continuity from the ECU back to servo to rule out a broken wire. If all that is good then its the A\C ECU. Will post back later.

Bax

 

I found the problem. When I changed the park indicator bulb , a few weeks back ,I bent one of the pens on the AC ECU. It was actually bent under the connector. I used a small screwdriver and needle nose pliers to line the pens back up. I plugged everything back in and the new servo is working.

So that my friends would be user error

So now I have a spare servo and radio. LOL

Bax

 

Thank you for posting the root cause.

You can put that servo in pay it forward or classified ... there are plenty of takers (me included)... hopefully you will be able to recover most of the cost or good karma.

Salim

 

Posting the servo in karma section.

 

Heck, hang on to the servo. Keep the car another year or two and it's almost a given that you will need it.