I was able to order motor RF370CB and the fit is perfect. However, for some reason something is still wrong with the servo. It seemed to work still when I used the other original motor as a test, but now with this new motor the servo does not function properly with the control panel. i see the arm moving when i plug in the electrical connector so i know that the motor at least works. however, it just does not move when I use the control panel to change the mode. I'm pretty sure I can hear something moving inside the servo, and the fact that the servo worked with another motor leads me to believe the plates are ok. pretty lost right now and probably won't attempt to fix this part unless anyone has any ideas.

 

I can't tell if you are having an issue with your mode servo or air mix servo. Can you restate which servo has the issue and which servo you took the motor from to make it work?

 

hsmac: Where did you get the idea to use RF370CB? I had a old thread where I had narrowed to a potential match. I will try to dig that thread up.

When you say it fits perfectly, physical fit, connection to the electrical tabs, length of the shaft, dia of the shaft, direction of rotation. rpm etc

There are two models 11670 would be better among the two as it provides more toque, but will draw more current.

It would be great to find the right motor.

Salim

 

i read through the threads and looked up the motor on the website. i think the 081100 is the only one i could get individually so i decided to try my luck.

i already put the motor in so the fit is definitely close enough if not perfect. it did seem like it might be a little slower than original so maybe the other is more appropriate for this application. i don't have a background in this field though and am not sure if it is not drawing enough current. like i said, the arm turns when an electric signal is sent to the motor, but for some reason is not working in conjunction with the control buttons. since it does turn i can only assume that that is not the issue.

 

Without getting into details, the model 11670 has more strength, so it should be able to overpower the mechanical resistance to the arm bit more.

Under no load (without mounting) the servo in the RX, but electrically connected, does it step through the positions as you change mode?

During disassembly, one has to mark the position of the arm and place it back exactly in the same position. The wiper inside tells the motor to keep spinning or reverse spin, but the what angle (position) of the arm is factory set during assembly.

One way to confirm is to cycle the servo (without mounting) and temp mark the extreme motion of the arm and then park it in the middle position. Then on the RX move the lever by hand to each extreme and park it in the middle. Now try to install the servo and see if the arm and the lever naturally align. If they dont then remove the arm on the servo and reattach at the spot dictated by the lever.

Salim

 

that's my point. when i plug in one connector the arm starts to move back and forth, so i have to assume there's no mechanical resistance. i have not mounted the servo as i am testing first, so under no load the controls will not operate the servo. one strange thing is that now only one connector will even move the servo arm while the other one won't. aren't both electric connectors the "same?"

i'm pretty sure it is not a positioning issue.

 

Isn't there feedback signal based on wiper inside and the sending unit would respond differently. The motors are dc but the wipers and the feedback make them servo.

Now if without load, the arms do not move, I would say the problem is with the wipers. With load if the arm does not move then it would be underpowered motor (model).

Salim

 

sorry, i don't understand what you're saying. are you suggesting that the other motor model will work?

 

Assuming the position of the arm is correct
under no load ... servo pulled out ,,, if the arm can move, but once you install it and the arm does not move then we can draw 3 possible conclusions

1. The lever in the RX is stuck and requires too much force which the motor can not provide
2. The motor is too wimpy to provide enough torque and the other model with more torque would be more apt to do the task

3. The assumption that the position of the arm is correct is wrong and or there is mechanical problem with the servo (mechanical includes the wiper connections inside which may be pitted or missing).


Salim
<FYI: Other than academic interest, I have long given up on repairing the servos. Poor things are overworked in Lexus and if folks use AUTO the mode should last about 8yrs (salim's guess)>

 

i think you misunderstand what i'm saying. at no point have i tried this motor with the servo connector to the damper (not screwed in/mounted onto the vehicle). so far i've only tested it with the electrical plug and left it dangling. when i use one plug the arm moves, but not with the other plug. the arm does not move with either plug when i try to use the control buttons to operate the servo. to me, this suggests that the motor is powerful enough, but it is possible there may be a disconnect with the current or some kind of signal. regardless, i haven't been able to find the other motor anyway, and like you probably won't spend more time trying to solve this issue. i put my working motor in the air mix servo and will just leave the mode servo, which i don't really use anyway, motorless. i may look for the servo or motor in my other older lexus that we don't drive and try to swap, but it is not a pressing issue. thanks for the feedback!

 

what is the condition of the traces on the servo gear? if worn down, enough... the brushes can't contact .

 

Post 73 has bad tracks around 5:30 to 7

I have never opened up a good servo, so my answer is based on observation and not fact.

Salim

 

Hi Salim,

Is any special tools and technique to remove the screw hidden at the back of the two tubes from the heat core?

Thanks

Raymond

 

I think it is used to control the movement intervals ( or distance ) of the motor.

Raymond

 

Access to screws can be hard, try different screwdrivers. I have couple of screw drivers which make a 90 turn (look like allen keys) and they one has to push them down to keep the phillips head engaged. Harbor freight sells one with different heads and it ratchets.

The servo is a dc stepper motor with its position controlled by the dc pulses.

Look here for pictures
https://www.clublexus.com/forums/rx-...made-easy.html

Salim