The control switch for my outside power mirrors has suddenly stopped working on my 1992 SC300.

Any suggestions as to how to fix my mirror controls would be appreciated.

Two other things don't work on my car:
1, Telescopic steering wheel
2. Memory seats

I don't think the telescopic steering wheel or the memory seat control are related to the power mirrors but thought I would mention them.

At one time the memory seats were working but the telescopic steering wheel has never worked since I acquired my SC300 several years ago.

 

If I recall correctly when my SC's Mirror Control ECU went out my seat and telescopic memory function also stopped working... although by that time I had already swapped out my factory original seats and installed Supra MKIV seats so it was really just the steering column memory function that stopped working.

While it is possible that your control switch and joystick for the power mirrors stopped working the more likely culprit is a bad Mirror Control ECU.

A new one for a 1992-2000 SC300/400 is Lexus P/N 89430-24020 and they are still available brand new. Shop around a bit for a good price on it. Try MyLParts with the Clublexus discount code or Amayama.

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The telescopic function more than likely will require a brand new telescopic motor. Again, I'd shop around on it for price but even with a very discounted price it is a very expensive motor. I'm looking at getting one of those myself soon if I cannot find a way to rebuild the original telescopic motor.

The tilt motor is almost always an easier fix as long as it is still good since our cars use the older plastic gear in column design that older LS400's use.

 

Thanks much for the info.

My power seats still work but my telescopic steering feature has never worked for me. There is no noise when I attempt to telescope the steering wheel in or out.

The tilt feature on my steering column still works just fine.

From what I have read, replacing the power mirror control is apparently a fairly difficult task.

It looks like there are plenty of used power mirror control modules available. If I could do the replacement myself, I might try one of the used modules. But, if I pay a shop to install the module, I'm sure that the labor cost might justify buying a new module. Any thoughts??

 

If your telescopic function is totally dead then it is possible that the motor itself does need replacing. Good that your tilt function still works. The tilt motor is the easiest of the two to replace... should it ever need to be replaced.

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The mirror control unit isn't incredibly hard to get to but it does have one truly awful 10mm bolt holding it in from an extremely difficult to reach location. I have published a DIY writeup (no pictures but a LOT of detailed step by step instructions) describing how to take your original one out. Someone else recently posted their own DIY for this as well. The good news is that once you remove your original Mirror Control ECU you will only need to re-install two out of the three bolts that Toyota had holding the original one in. Two of the three bolts are very easy to get to. It is just the horribly placed one up at the top of the unit's built-in bracket that is a bit of a nightmare.

Here is the DIY writeup I made showing how to replace the entire Mirror Control ECU for a new one (or a good working donor):
https://www.clublexus.com/forums/per...scription.html

And here is a more recent one which takes a different approach-- opening the ECU's metal casing while it's still bolted in the car, swapping the internal logic board out for a good working donor board and then re-sealing the casing:
https://www.clublexus.com/forums/per...0-minutes.html

Two different ways to go about getting a good Mirror ECU into your SC.

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As a side note I kept my old bad Mirror Control ECU and it did not occur to me to look up the capacitor part numbers inside it and order new ones from Digi-Key or Mouser for the purpose of replacement to attempt to make it work again. I may try this but I'm not sure if it would work the same way it works for main engine ECUs that require re-capping.

 

WOW, that is a great writeup but it most likely is too much for a youthful 84 year old duffer like me. In fact it looks to be almost too much for most folks.

I now see why several people have suggested just leaving the old one in place and zip tieing the replacement module. Or just manually adjust the mirrors when necessary.

In my case, I am the only driver of my SC300 which I treat like a collector car. I had a 5-speed SC300 that I bought new in 1992. It was one of my all time favorite cars. Wish I had never gotten rid of my first SC300. I acquired my current 1992 5-speed SC300 several years ago. It has 83k miles and still drives like a new car. But the power mirrors have stopped working along with the memory seats. The telescopic steering wheel has never worked for me.

I wonder what the Lexus dealer charges to replace the power mirror module. Or would you trust the dealership to do it?

Thanks again for your most helpful and insightful information.

 

depends on the dealer, but I wonder if they even have a new one availalable, so many parts are discontinued. They may not even have much experience working on the old SC as so few people have them they probably only train their techs in the newer lexus models. A better bet may be to find a quality indy repair shop near you.

 

The part seems to be readily available, either new or used:
https://www.lexuspartsnow.com/parts/...430-24020.html

There are quite a few used ones out on EBAY.

From what I have read, Lexus and Toyota both used this part on several different models.

I will call the Lexus dealer and ask what they would charge. But a good independent garage may be the answer.

There is a large independent Lexus shop in Houston: Clear Choice Independent Lexus Specialists

But when I checked with them about repairing my telescoping steering wheel problem, they quoted $3200 which seemed astronomical to me and that was three years ago so they might charge even more now. But, out of curiosity, I might call and ask them what they would charge to replace the power mirror control module.

 

I had thought that my memory seat function wasn't working.

But I found some old notes reminding me that my emergency brake has to be engaged in order to set the memory seats. This may be unique to 5-speed SC300s.

Anyway, I can scratch the memory seat problem off of my worry list.

 

For the power mirrors, check fuse #7 by the drivers side kick panel in the fuse box. If you're lucky, you blew a minor fuse.

I would be surprised if any Lexus dealership would still be able to obtain OEM SC parts from the 90's, but I definitely wouldn't put it past them. You will pay premium pricing, however.

On a side note, the telescopic function on the steering wheel may just be as simple as the pinion gear has, over time made it's way off the gearing mechanism and it just needs an extra washer or two to push it out half an inch, if memory serves. I will look and see if I can find a DIY or pictures.

 

theleme, please allow me to first say that I am glad to have a long time owner such as yourself here who appreciates these vehicles as the contemporary classics that they are. I completely understand where you are coming from.

And driving and enjoying a 5-speed manual SC at 84 is inspirational to me!! I hope to be doing the same myself someday!

You are correct in that for the 5-speed manual models you first have to raise the parking handbrake in order to engage the memory seat, mirror and steering column functions. However you will find that with your current issues only the seat memory and column tilt functions will respond to memory control.

You very likely have to replace the mirror control unit but before you do I second SC400Slide's suggestion to check fuse #7 on the driver's side kick panel first. If that fuse is not blown then the mirror control ECU will be the way to fix it.

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To acquire a brand new one (and they were only made for the 1992-2000 SC300/400 models) which are indeed still available brand new I recommend checking the shipped price at MyLParts with the clublexus discount code or Amayama with their Fedex shipping option (they order the new part from an Osaka, Japan Toyota dealer and ship to you internationally).

I completely agree that the process I outlined to replace the unit does require some physical exertion and resilience. I do not recommend doing it yourself if you're 84. I knew well enough to do everything very slowly and carefully so as not to risk putting my back into any difficult situation. That's the primary reason why the job took me as long as it did: it was not easy to do and I prioritized my physical safety first at the expense of getting the job done faster.

That and I did not want to take the dashboard out to get to the hard to reach bolt since that is a tremendous job all on its own. I strongly recommend that anyone attempting to do this mirror ecu replacement always prioritize their physical safety first and the job second because it's in a hard to reach place that requires you to be a bit of a physical contortionist to get to the very top bracket bolt.

Once the unit is removed however, installing another one is very easy. You still have to do it while laying on your back in the footwell with goggles on (because random debris *will* fall in your eyes looking straight up into the pedal area) but you only have to reinstall the lower two 10mm bracket bolts and they are enough to hold the new Mirror ECU in place.

It's getting a factory original Mirror ECU removed for the first time in an SC300/400's service life that is a major pain to do because no one will have ever removed that awful upper bolt before. No one in their right mind would ever want to replace the top/upper bracket bolt when the lower two are all that are really needed.

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The dealer will undoubtedly charge a decent amount in labor for this and their method may actually involve removing the dashboard to get to that one pesky bolt. By the way, I always recommend that only the two easier to get to mirror ECU bolts be replaced. The difficult one is not necessary to replace as the other two keep the unit very secure by themselves.

The alternative methods for you would be to show the outlined procedures posted here to a good and trustworthy independent mechanic (I would not trust work on these cars to just any repair shop) or to use the zip-tie method or logic board replacement method.

However you do it, please take care because it is not a procedure worth risking your back over even if you're in peak physical shape.

The telescoping function more than likely will require you to purchase a new telescoping motor for. Those are also still available (as is the tilt motor) and due to their sheer price I also recommend you try Amayama with Fedex shipping for that part as well. A new Mirror Control ECU for the SC is far cheaper in comparison.

Replacing the steering column tilt motor is not very difficult to do yourself but the telescope motor does sit farther back into the column assembly and requires a bit more work to get to. I am not surprised at the $3200 quote several years ago. These are procedures that Lexus dealer technicians will only have the factory Technical Service Repair Manual to use for instructional references and few current technicians will be familiar with any jobs like these on SC300's or SC400's in the year 2020. That is not to say that they can't do it and do it well but it will be an involved job that ample time will be budgeted for to make sure they get it right.

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It's better to go with a good independent repair shop for that job unless it's something you can do yourself. Also, this is not an option in all cities and states but finding a good and trustworthy Toyota dealer that will work on Lexus models is also another good alternative to the Lexus tax for some common big repair jobs.

I use a Toyota dealer in my area that will work on Lexus vehicles as well as a trustworthy Toyota/Lexus independent repair shop for anything maintenance or repair work that I will not be doing myself. The Lexus dealer is always an option but I don't use them for service, only occasional parts orders that I need immediately and cannot wait for. Multiple options are good to have when owning an SC.

 

I've messed with a spare steering column, and I'm not convinced the common telescoping motor failure is serviceable. I suspect that $3200 quote is basically a full rebuild or replacement.

I've been waiting several years for someone to prove me wrong.

 

t2d2, do you mean that it is not possible to rebuild the SC's telescoping motor (ie: you must replace it with a brand new one) or do you mean that it is so hard to get to it that you have to remove the whole steering column assembly and dismantle it on a workbench just to remove and replace a bad/failed telescoping motor?

 

It's been probably 5 years, so going from shaky memory...

Getting to and removing the motor is the easy part. The hard part is unplugging it. The connector and tab are oriented the wrong way for any normal-jointed person to reach.

The motor unscrews from the column, at which point all the ball bearings packed in around it implode. Or, they might have been elsewhere in the column's slip joint when I was further exploring. At any rate, I had little luck getting them back in place to reassemble. And that was on the workbench. Doing so in the car would be a nightmare.

After going through all the trouble, the motor itself wasn't the problem, as I recall. It fits the general wisdom that electric motors don't usually fail...it's typically something else related to them that stops working. I think that might have been where I started exploring the rest of the column assembly, to see why it wouldn't move if the motor worked fine.

It wouldn't surprise me in the least, if the real answer turns out to be, the columns just need fresh grease. If only they had some sort of access port...

After that unsuccessful adventure, I fashioned a cover where the motor would go and left it out, after getting the tele position where I wanted it via numerous start-ups, moving a mm or so each time. Tilt is pretty nice for driving comfort. Telescoping is very low on my list of useful features. Combine that with it being probably the least reliable feature on the platform, and...good riddance!

 

Again, I can not tell you how much I appreciate all your very helpful info.

I need to ask a dumb question. How is the best way to access the inside fuse panel? Do I need to pull back the kick panel carpeting? The carpeting seems to be pretty well secured.

Although I am somewhat of a purist, if the problem is indeed the control module, I now lean toward using the zip-tie method.

Last week, I took my Lexus to an independent shop that specializes in Lexus, Toyota and Honda repair. But they seemed pretty stumped by both the power mirrors and the telescopic problem.

Bur as soon as I know how to access the fuse panel behind the driver kick panel, I will check fuse #7. It would be wonderful if that turned out to be the problem.

And, yes, 84 sounds old. But I am very active and stay very busy.

And I like these two Satchel Paige sayings:
"How old would you be if you didn't know how old you are?"
"Keep moving. Don't look back. Something might be gaining on you."

 

I looked again for the the fuse box at the driver kick panel.

I find a black box that is partially covered by the kick panel carpet.

It appears to have a removeable cover but thought I would check before trying to get it off.

Does this sound like the fuse box?

If it is can I access fuse#7 just by removing the black plastic cover?

P.S. I wrote an earlier response to you but inadvertently posted it under t2d2's post.