Rear Wiper Relay
 

Where would I find the relay for the rear wiper on a 2008 T4R Ltd?

I'd call a dealer and ask. Your local dealer may have it in stock to pick up today or can get it shipped in pretty quickly. If not, I've had good luck with McGeorge Toyota online parts, they seem to have the best online prices and ship quickly. Call and try to talk to Alex or CJ, if you explain you're on the west coast, they'll send you a quote on email or just tell you the PN. From there, you can order from them or look somehwhere cheaper. Although if they just give you the PN, I'd just go ahead and order from them out of courtesy, they seem to be cheaper than toyotapartsdeal most times anyway

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Sorry, I should have clarified -- where would I find the part inside the car?

Shoot, sorry for misunderstanding. No sweat, unfortunately I'm not sure haha. If you haven't already, I'd check the fuse box in the engine bay and try to see if any of the labels in there could match something recognizable. I think I've seen a pic somewhere with it saying R WIPR or something along those lines

The back door ECU runs the rear wiper. There is no independent relay for the rear wiper. What exactly is the issue?

The rear wiper won't turn on after a battery is disconnected unless you roll the rear window all the way down and then all the way back up first.

So I did a big bad thing. A stupid thing. I replaced the battery but forgot to get one with reversed poles. Under too much stress lately, I didn’t even think as I hooked up positive to negative and negative to positive. It wrestled havoc. Totally blew out 11 fuses, including most of the big ones. My TPMS light is now on perpetually. My airbag light too. It fried my SoundLinq Bluetooth audio adapter. And the rear wiper blade goes on non stop. Can’t turn it off. Can’t change the speed. Can’t use rear wiper fluid. The only way I can get it to stop is by opening the rear window. So for now I just keep the window open a hair. But I’ve gotta fix this.

All the fuses have already been replaced. I’ve done the up/down reset many, many times.

I was hoping there’s a relay for the rear wiper, not just an ECU. Because the cheaper potential fix could be a relay whose contacts fused or melted from too much current.

SO... if there’s no relay and no fuse problem, I can’t think of anything it could be other than the ECU.

Anything I’m missing?

Unfortunately our nearest Pluck n Pull has no 4th gen 4Runners to grab an ECU out of a junked truck. Actually none of their locations anywhere do assuming their inventory system is accurate.

Don’t want to pay Toyota prices if I can help it.

Or might it be something else entirely?

Get an electronic copy of the factory service manual. Test your rear hatch ECU per the manual.

If it is bad then go on partsouq.com and enter your VIN number. Find the part on the exploded views. This will tell you the part numbner.

Search that Toyota P/N on eBay and other places online and you can find one without spending an arm and a leg at the dealer.

Problem fixed; my rear wiper is back to normal. Thank you everyone for the guidance.

What was the fix? If someone stumbles upon this thread later, they're gonna want to know.

Well I ended up taking it to a mechanic who specializes in electrical systems, to make sure of the diagnosis before I bought any parts from somewhere.

Honestly, I lucked out.

It was just another fuse. Guess we only thought we replaced all the ones that needed to be replaced.

The mechanic said the second most likely scenario would have been the ECU for the rear gate that handles all functions on board the gate as he hadn't found any other shorts or other issues in the electrical system.

All the other problems stemming from this s**t show were also fixed by replacing fuses/relays. All told, my stupid escapade with the battery reversal caused about $550 in damages and repair bills, including, IIRC, 14 blown fuses including most of the large ones, and 3 relays.

The only remaining problem now is the Bluetooth audio/music adapter I installed a couple years ago. It used to connect through the disc changer port. It is totally unresponsive now, but I haven't and probably won't replace it any time soon. I'll just go back to using the aux cable.

Could have been worse I suppose. But still....#Eff2020 ;-)

On the upside! This whole ordeal seems to have incidentally fixed my moonroof problems -- weird noise and failure to auto open/close. Not sure if replacing a fuse, relay, the battery, or what happened to do the trick. But knock on wood, it's been working normally again. Hasn't done that in over a year.