Fredmahan

Ladies and gents, my 1993 SC300 manual has had the flasher relay go bad. The Lexus part number is 81980-24020, but it's been discontinued, and I can't find one with that part number anywhere. Does anyone have a relay to sell, or do you have an equivalent part number in Toyota or any other brand? Ebay and internet searches have led to conflicting results. Any help would be appreciated.

Fred
fredmahan@hotmail.com

gerrb

iTrader: (34)

you have the right part number .. are there no pull a part in your area ?

For Wanted to Buy Ad thread .... put it at the Market Place section.

LeX2K

EP35 flasher should fit just about any auto parts store will have them. Or if you're picky and need OEM salvage yard.

KahnBB6

iTrader: (5)

Unfortunately the Novita EP35 and Standard Motor Products EFL9 flasher relays are three-pin whereas the 1992-1994 SC’s have 5-pin flasher relays.

I bought both an EP35 and EFL9 just to test with as future replacements and neither are suitable.

1995-2000 SC’s may be able to use either aftermarket flasher relay but not earlier SC’s.

In another thread I’ve started researching the possibility of how feasible it is to rebuild a factory 81980-24020 flasher relay. I’m advising people hold onto theirs even if the unit is blown in case it becomes possible to replace some of the affected internal parts.

It will take some experimenting and physical inspection of the OEM relay first. I’ve thrown the idea at O.L.T. and I may try contacting Yamae (former Toyota ECU and electronics engineer) about it as well if he is still active on the forums.

Unlike late-1994 and 1995-2000 SC’s there is no other vehicle Toyota or Lexus produced which cross references to this specific relay part number.

https://www.clublexus.com/forums/sc-...nal-relay.html

Fredmahan

geerb --

Thanks for the suggestion. Didn't find any sources on line, but found the relays in cars at a local "pull" place. It sure is hard to get to, especially in a dead car where you can't move the seat back, and the carpet is all wet!

Fred

Duck05

You might want to contact Tanin and see if they can repair one of your defective units.... Nothing to lose to ask...

Fredmahan

Duck05, thanks for the suggestion. I just sent them an e-mail.
Fredmahan@hotmail.com

KahnBB6

iTrader: (5)

Fred, depending on what Tanin replies, they may be interested in the ongoing research thread about the workings and components inside this flasher relay for 1992-1994 SC's:

https://www.clublexus.com/forums/per...0-24020-a.html

ELACalumni

I live in the Los Angeles county area. There are no other 81980-24020’s at any of the dealerships or junkyards that I’ve contacted.
I’ve been looking at other aftermarket 5 pin flasher relays.
I’ve got two (different ones) on order vía Amazon. I hope to use the on line Sc300 diagrams to extrapolate where to manually connect the flasher pins to the factory flasher receptacle- hopefully, I won’t fry anything too bad.

KahnBB6

iTrader: (5)

ELACalumni, be careful. I wouldn't just plug anything into the socket. See the thread below where we have been getting into exactly how the OEM 1992-1994 SC flasher relay works. It uses a standard 5-pin Bosch style relay pin setup but the pins do not conform to the function of any common 5-pin relay.

https://www.clublexus.com/forums/per...0-24020-a.html

There is quite a bit of documentation amassed already but now at current time we're fast approaching the need to fully understand how a professional electrical engineer designs a compact twin-relay chip controlled flasher relay unit (accounting for all electrical values necessary) to go further with any custom solution.

The OEM 5-pin relay we have has totally custom function assignments, is timed by a few specific capacitors, resistors and transistors and has a 6-pin digital controller chip assigning functions to not one but TWO relay mechanisms inside the OEM 81980-24020 unit. It was designed this way in order to spread the electrical load over the two internal relays (one relay for each side of flashers) for better long term durability of the components and electrical contacts.

^^ That is what makes this a difficult problem to find solutions to. It is not a conventional flasher relay at all.

The 1995-2000 SC's and Soarers used a more conventional and easier-for-aftermarket flasher relay and flasher circuit design.

It's slow going to figure out a way to make an aftermarket equivalent relay. At the moment the first most promising bet is to identify all the replaceable capacitors, resistors, etc. that can be sourced from Digi-Key or Mouser in the *exact* type originally used by Toyota, desolder the old ones and replace with brand new ones and see if that alone can fix a bad relay.

These do show up on eBay from time to time (maybe just not at this moment though). I highly recommend you KEEP any 81980-24020 relay even if you've confirmed that it is bad because if/when we do discover a way to repair or rebuild one of these very specific Toyota relay units it will come in handy for owners to have their original relay assemblies to get repaired.

No other Toyota or Lexus model used this part other than the 1991-1994 Soarer Z30.... which has the same exact relay unit only with the part number 81980-24010 and perhaps a *very* minor electrical difference accounting for the digital instrument clusters in those cars (or maybe they are exactly the same relay electrically but just using a different part number). Just the same with those early Soarers there is no aftermarket equivalent for their OEM relay and those are discontinued as well.

We have to figure out a rebuild or custom solution (that 100% works reliably) ourselves within the community going forward. Keep the bad relay that you have for future repair work even when you do find a working good used one to replace it with.

LeX2K

If someone sends me an original I'll clone it.

KahnBB6

iTrader: (5)

If you're capable of that kind of ground up electrical engineering then such a thing can be arranged.

Have you already read through the current 81980-24020 dissection thread to get an idea of where we're at with knowledge and electrical schematic info so far?

https://www.clublexus.com/forums/per...0-24020-a.html

I have looked into it as much as I am capable of and Yamae and O.L.T. have provided some very valuable insight and even a bit of reason from older Toyota electrical engineers as to why it was designed this way in the first place in the very late 1980's but beyond identifying and sourcing any available replaceable small internal components (to desolder and replace with new caps, resistors, etc) that aren't proprietary Nippon-Denso I can't go much further with the project myself. I am not a professional electrical engineer capable of redesigning an entire part like this from scratch with all new components and a brand new custom printed circuit board.

If you can take this further than we've been able to so far then I know I and others with 1992-1994's are interested.

LeX2K

I have many, many years electrical/electronic experience. Can't promise anything of course, but in my view this is simply two flasher circuits in one box. It is an over complex design to say the least, and an answer to a problem that didn't exist. The single relay Toyota flasher is very robust and the relay contacts can easily handle the current required. It's not like the SC had way more lights/much higher load than any other car.

Why Lexus did this is baffling to me. My thinking is it should be possible to modify a single relay flasher, or simply combine two flasher relays to do the same job as the original.
I have.

edit - forgot to say, this proves Lexus tried to fix a problem that wasn't there, how often does a Toyota/Lexus flasher relay go bad? The answer is rarely, but in this case the dual relay flasher goes bad! This is the overly engineered stuff I expect from a company like BMW or VW not Lexus.

KahnBB6

iTrader: (5)

I have to agree with you as well, especially since they changed the signal flasher relay setup for late 1994 to 2000 SC and Soarer models to a more conventional single relay design (and likely different body wiring to support this). According to Yamae's contacts the twin internal relay flasher unit approach was done on all high end and luxury Toyotas in the 1980's through early 1990's to preserve the electrical contacts over time. But as you say... was it *really* so necessary even with the conventional bulbs of the time? Especially when these cars all switched to a more conventional flasher relay during a mid-cycle model revision update?

Anyway, perhaps we should switch further discussion to the flasher unit dissection thread.

And I'll PM you about this shortly as to what you'll need beyond just a flasher unit if you do want to take it on. It is understood that there are no guarantees but it sounds like you can take this farther than I'll be able to. I just hope we can find a good and reliable rebuild or replacement solution of any kind that all 1992-1994 SC and 1991-1994 Soarer owners can benefit from... since these relays are no longer sold new and have no aftermarket equivalent.

1992SC300M

I too need to source a solution for fixing or replacing a non functional flasher relay for my recently purchased 92 SC300. Any help is appreciated.