carguy07

Are you sure you're not just hearing the other servo?

chenxingha

To Salim:

The Mode Servo, old or new, appears dong their jobs fine because even when the rapid clicking noise occurring, Mode Selection had no trouble going through the mode sequence - I was using the motion to stop the noise. Air came out according the selected mode without any hesitation.

With that kind of rapid clicking ad for very long time, one would expect something physical damage would be visible. But, as my early photos showed with the old unit, there aren't any evidence to point to any physical damages to any of the parts inside the Mode Servo unit case.

On occasions I do hear low-frequency noise low volume turning noise coming from the center compartment below the gear shift handle. Does any body know what are the stuff inside that enclosure?

chenxingha

To Carguy07:

What is the other servo you are pointing to, and where is it located?

carguy07

There are two, "mode" & "mix"

carguy07

Another shot

salimshah

One simple solution to diagnose the problem is ..when the sound happens touch the suspected component.

Salim

SVRX300

Thank you carguy07 for the two pictures. I didn't know there is the 'mix' servo.
I fixed the 'mode' servo so the loud noise is gone. The very low noise (I call it grumbling noise) could very well be cause by the 'mix'servo. When idle, I can hear it; when driving, I can't.

davidyal

Does anyone have a photo of what positions the damper arm on the Mode servo should be in to get air to the 1) feet 2) face 3) defrost? I've been trying to move it manually and can only get it to feet and defrost. IS this all controlled by the mode servo? or is there another control in play to get air flow to your face like the blower control or ECU?

Lexmus

When I worked on my mode servo, it appeared that all vent choices are controlled by the mode servo, as the servo moved and changed the arm position each time the A/C mode button was pressed.

chenxingha

To Carguy07:

Thank you for pointing out the direction to air mix servo. On my wife's 2000 RX300, just below the Mode Servo is a white plastic enclosure. Based on your photos I guess the mix servo is right behind it.

Are there photo instructions on servicing this mix servo? In repair and replacing the Mode Servo I managed to break a couple of plastic locking tabs while trying to figure out opening the case. With instructions the damage I could do will be limited.

My daughter's 2000 RX300 used to have (on explainable occasions, not frequent) this low-frequency low-volume grumbling noise, even though A/C and fan were off. We no longer have this RX300. This low-volume grumbling noise appeared (on and off by itself, follow no particular patterns) on wife's RX300 recently.

Thank you.

salimshah

There is always air flow happening even with the AC off. Occupants won't survive in the cab if it was air tight.

In Auto mode, the mode servo keeps moving and redirecting the air flow to keep the cabin fresh. Folks who switch to Lexus from manual set air direction notice that the cabin air is much fresher in feeling and the deep down it is the mode servo at their service. The mix servo is not subjected to the wear the mode servo is subjected to and tends to outlast much longer.

Salim

Guitarboy

My lower servo is hunting and clicking and after cleaning it, it wasn't much better so it's time to just replace it.

It has 063700-7061 printed in white on the side, I don't see many of these servos for sale, and the ones that are available are really expensive.

However, there are lots that look the same but have different part numbers like 87106-30341 on the bag and 063800-0530 printed on the cover, or 87106-30351 on the bag and 063800-0540 on the cover, etc.

Is there a functional replacement for the 063700-7061 that doesn't cost an arm and a leg, and if so, what would the part number(s) be ?

Thanks for any help !

salimshah

Servo is generic term. You need the precise part number to match [or check with Lexus if the part has been updated with a new number].
Yes the replacement servo is expensive. But it is used extensively as you drive in Auto mode.

Salim

chenxingha

To Carguy07:

How to get to the top screw while the 2 aluminum tubes block the access (refer to your second photo)? The 2 tubes run in parallel on top of the screw and do not appear to have gap that would allow a screw driver going through.

chenxingha

I am stuck at loosening the top screw pointed by the RED arrow in the photo. There is less than a finger space between the screw top and the 2 aluminium tubes which are running in parallel with no gap between the 2 tubes.

I need advice about getting this screw off.

Thank you.