sakataj

iTrader: (182)

that servo that is opened, is of the temp servo.... i think. its been a LONG time since i did this..


does your servo look like the one sitting on the floor mat in this picture below?



if not, it should look like mine, just reversed.which servo did u replace? the drivers side temp servo you posted in the first post....its also the same temp servo, just reversed

Kbueno

I would also strongly suggest a new servo unless you're very confident in the repair. The labor to get to it is a PITA.

sivikvtec

Is it just me, or are some of the teeth on the middle gear broken off (top of the part of the gear that stick out to contact the large gear)??

sakataj

iTrader: (182)

X2

I dont think so.....maybe they were. i still have that servo so i will have to check

jonathancl

Thank you, fingershop, for saving me $160. I was about to order the servo until I read the description of the problem with the lubricant and potentiometer.

If I had cycled through the air flow modes, it would function normally again, but the tapping or clicking would always return.

My servo was as described in this thread: the potentiometer disk very much covered by the gear lubricant.
I wiped it clean, reassembled and tested. All fixed.

The hardest part is getting the servo out; the rear screw is nigh inaccessible.
Getting the servo back in is a little tricky, too.

This is a much easier DIY than the door lock actuator since you can actually open the servo assembly, unlike the door lock.

It's the same labor whether you replace or repair. Opening and cleaning the servo is by far the easiest part.

fingershop

That's great! Glad you got yours working again.

I will guess that the lubricant is applied to the disc at the factory, to keep the potentiometer's stripes from wearing too quickly. I'm not sure which is better, to leave some un-contaminated lubricant on the disc, or to wipe it clean. I left some on mine, just to be safe.

I used my shortest 3" phillips driver to get that one screw out, my longer ones just wouldn't fit in the cramped space near there.

jonathancl

The lubricant is applied to the other gears in the servo, but high heat and time allow it to flow onto parts it shouldn't. My wife's old trailblazer had the SAME issue in the windshield wiper motor assembly, and my living room stereo volume control has issues from time to time from its lubricant.

Three totally different things with exactly the same problem fixed exactly the same way...

fingershop

Its interesting that you've seen the same issue in other items. I wonder though. If heat caused the lubricant to flow then I should have seen a puddle of it at the bottom of the servo case. But no puddles. All the lubricant was right on the gear teeth, and in a big blob at the screw gear, and on the copper contact. On the disc there were a few small circles of the lubricant that looked to me like they were applied that way at the factory. And no drip marks anywhere.

sivikvtec

any updates OP?

are they still working fine?

lexus ASM

I dont know if this is relevent to the post but it is possible that this failure in design has alot to do with the temperature that these cars are driven in. If you have a car whos owner keeps the temperature at or near the outdoor temp, then more wear would occur in a smaller area.

lyonkster

Well, maybe we are discussing different model cars here, but I was not able to get to this point with my '01 GS430. As I said here, I could not get to the contacts/potentiometer until I broke off the arm that is attached to the gear. At that point the servo was ruined.

So, I am curious, can someone post a photo of how they got to the potentiometer without breaking off the arm?

jonathancl

No need for a photo. The gear stays attached to the side of the housing to which the gear and arm are attached. It appears just as in your photos...except that the arm is not broken.

lyonkster

Well, on mine the arm was fused to the gear, there was no way to get it off without breaking it (believe me, I tried). Without getting off the arm, I could not get to the contacts. Are you saying you were able to get the arm off the gear without breaking it off?

casey_c

The mode servo is different from the temp servos. When you open a mode servo, you will see the contacts. On the temp servos, you will see the opposite side of the potentiometer contacts. I wasn't having a problem with my mode servo, but I opened it up and cleaned it anyway.

My passenger temp servo was making a lot of noise. I opened it up, greased the gears, and noticed that there was quite a bit of slack in the big gear. The contact fingers press on the gear like springs and I surmised that over time they had lost solid contact. I took out a bit of slack by gluing two washers between the outer case and the shoulder of the plastic arm. This pulled the contact fingers tighter against the potentiometer contacts and seems to have fixed the problem for me.

lyonkster

Ah, that explains it, thanks.

I actually tried a similar thing with mine, by putting a washer underneath the case. It seemed to work for one of the servos, but not for another. At that point, I went the route of saying "I really want to just be done with this for the next 6 years and not make this into a semi annual maintenance thing", so I just got the new servos and put them in. But I can see how some servos may be fixed by the washer or the grease, so more power to those who go that route.