Weird Dome light issue for just Drivers side Front and Back doors

How did you go about programming your
keyless remote to function with the replacement bcm?
I had a similar issue with bad led bulbs and replaced the bcm with a used model, but have not been able to get the smart key remote keyless entry to work.

 

Actually, I didn't do anything. I changed out the ECU and everything just worked.

 

Your runner have a smart key? Maybe I got a bum replacement bcm? Or one not compatible with a smart key? Part numbers from both are exactly the same.

 

Check the other forum. There’s a similar thread there. If seems the BCMs have the same hardware part number label on them from the manufacturer. But they are programmed with different firmware depending on the trim. So a Limited BCM will have different functions than an SR5. You’d think there would be some additional post-programming stamp on them to indicate the trim application. You may need to compare every marking on your old one to the new one to find any difference. Maybe take it to the dealer to figure it out.
Check out the advise here:

 

Yep, confirmed mxp has same part number for sr5 and limited but are programmed to function differently. Bought mpx from limited, installed and all is back to normal, plug and play.
Sr5 mpx for sale if anyone needs one.

 

@Old Red are you able to find parts specs for Diodes D022 and D024? i just bought a 2012 TE and it has this issue. i pulled the BCM and confirmed i have the same 2 fried diodes. i do micro mini soldering and repair, so R&R of those 2 parts might be much cheaper than buying a used BCM.

thanks in advance for any info you can provide! this truck has the chinese LED toyota logo projection courtesy lights, so this one must have been fried when the PO installed them. the other 3 doors work fine and i actually think it looks cool, but cool is not worth expensive repairs ever... LOL!

 

Is this switch set to door?

 

for me yes, that SWX would only keep front dome light off. i also don't have the door open indicator on the dash. i opened my BCM today and confirmed the fried diodes

 

@jbtaco2002 I don't have any specs as far as the values of each component on the BCM PCB. It's unfortunate Toyota does not provide that, as you are right, it would make repairs far easier/cheaper. I think that if you remove the other half of the black plastic case and look at both sides of the board you will see a burned ground trace to the 32 pin PCB header that interfaces with the cabin fuse box. The fuse box is normally fine when the BCM gets cooked.

IMHO, it's not worth trying to repair. Usually when these get fried by those junky Amazon LEDs and Projector lights there is more damage than is visible. You most likely don't have the door open indicator on the dash (via CAN bus) because something else is wrong in addition to the diodes. I would find a cheap used replacement and swap it in. You don't need to reprogram keys or anything like that. The BCMs are pretty much plug and play so long as it comes from a vehicle with the same ignition type as your original BCM (Keyed--> Keyed vs Push button.) Since you have a trail edition, you will need a BCM that is MS bus enabled for the drive monitor switch overhead, so it has to be a used BCM out of Trail edition.

I sent you a link I found on a BCM.

I really need to make a "Good BCM Practices" PSA or pdf for reference for people so they stop using these crappy lights. In all honesty, every circuit on the BCM should be fused. This is a design flaw for the system.

 

I believe @Old Red has the best advice, to replace it with a reliable BCM. But if you still want to experiment with a BCM repair you could remove the fried diodes, clean them up with isopropyl alcohol and see if you can make out the part markings on the top. If legible that might provide a clue to the manufacturer and the P/N.

If not, you could take a chance and order some SMT switching diodes of the same form factor with 3A forward current rating.
Don’t buy off Amazon, go to a reputable distributor like this:
https://www.digikey.com/en/products...TCBcDaIMoFsAuACAJgSwPZoKYGcV8MA7AcwBtcQBdAXyA

Be sure to check for blown traces and those SMT resistors might be damaged.

As Old Red said, there may be more internal damage that you cannot repair. But if you have the tools, skills, and time, why not give it a shot.

Good luck, be sure to post an update.

 

Old Red shot me a link to a BCM specifically for a trail, so i already bought that. my plan was to buy a $35 2012 camry BCM i found on ebay, size wise it looks identical, so my theory is the PCBA and components would also be the ~ the same on the board, since the circuits i'm sure are fairly universal for component specifications between Toyota models. makes sense to me, we'll find out. I'm an Electrical Engineer and was an ET in the Navy is well, so 2M circuit board repair is my specialty.

i'll post an update if attempted repairs are successful or otherwise ;-)

 

question for those in this thread that had the driver's side door courtesy light issue, is there a light that illuminates the gear shifter positions when headlights are on? i'm trying to figure out if that is supposed to light up, because mine isn't and it may be related somehow to the door not working. this 4runner is new to me, so i'm learning. thanks in advance!

JB

 

Yes, there is a small bulb down in the shifter housing that illuminates the shift position when the headlights are on. It’s probably burnt out. I think that is the only actual dash light bulb you can replace. All other dash illumination is LED. You will have to remove the top of the console and top trim piece around the shifter. 5 min job, all clips. Just remove the colored rubber cap of the bulb and swap that over. It’s one of those really small bulbs I think size 72 or E74. Don’t quote me on that though, I can never remember those little bulb sizes. Take it to the auto parts store to match

 

@Old Red dude... you frickin' rock man! really appreciate you!

probably gonna be asking a lot of questions as i settle into my 2012 TE, and start finding more issues ;-)

 

quick question Red, do you know if that shifter position bulb voltage/signal comes from the BCM?

 

attempted 2M repairs borrowing diodes from a Camry BCM, unsuccessful in fixing the lighting issue as was suggested may be the case, but i figured it was worth the try. obviously some other component somewhere took at hit when the short occurred. i only replaced the 2 obviously damaged diodes, but the third component right there may be bad also despite passing diode measurement on the fluke... and the diode on the back of the board as well. oh well. replacement BCM should get here Friday or Saturday, and hopefully we're good.

thanks again to those offering advice and help!

 

Happy to help! It's what the forum is here for. There will be no "use the search function" answers lol. There are a lot of useful and knowledgeable folks on here, so If I don't know it someone else surely will. You no doubt may have a few things come up as you get the 12' TE dialed back in, but it is a 4Runner so it might be three things max.

All the dash illumination is actually controlled via the BCM and speedometer depending on function. For the 2010-19MY which are essentially the same electrically, the 12V illumination (+) is output from the BCM (Green wire on most illuminated switches/control panels) and either goes direct to ground (No dimming) or dims via a grey wire (Dimming ground) which goes to the speedometer.

Now if you have the photodiode sensor on top of the dash, then that tells the BCM the ambient light and that info is relayed via CAN BUS to the speedometer which automatically dims the dash. So I guess what I am saying is that depending on function there are multiple signal sources, but one 12V+ lead. Do you have a copy of the FSM and wiring diagrams yet?

 

It was worth a shot. I'm not an electronics expert so a lot of the testing and messing around I have done with some of these parts trying to figure them out can be best put as a "caveman" approach. The only thing I can think that might also be bad would be a transistor somewhere on the board, or one of the MCU input/output pins. Thoughts?



I wish we could pull up circuit schematics, but Toyota doesn't have them available. They are manufactured by DENSO and my guess is all that info is proprietary. Even though some of the MCUs are marked with the Denso logo, I think the MCUs are either Renesas or Fujitsu chips but I haven't been able to figure out which exact ones. Would be nice to be able to fix these and or recode them to have more features like auto headlights, etc. Probably more trouble than it is worth.

 

Well, it was worth the good try. Usually with a catastrophic short like that a worst case replacement of all components in the shorted path works. But without the CCA schematics you don’t really know what all the parts are that need to be replaced. You could only go by their burnt appearance. This is probably a multilayer board and there could also be internal traces that opened up. As Old Red said, the MCU output must go thru a high current driver chip, or transistor, which could also be fried. You could try the shotgun replacement technique with more parts around the scorched area but it would be a guessing game without any real board documentation.

 

well, the ebay BCM came today(Thanks @Old Red ), and we are back up and running 100%! all lights, working, tested all MTS switches, crawl, rear locker, etc, everything functional.

i'm still debating on doing more component R&R on the burnt unit to see if i can easter egg it and fix it! but, taking the lower dash apart for the 10th time today, i realized i just want to enjoy my new vehicle for a while! lol
PSA no cheap LED's in your doors folks

thanks for all who helped and chimed in

John

 

Glad to hear it’s fixed! If you keep playing around with the toasted BCM and find a way to fix it/what all got cooked please Let us know. This seems to a recurring and somewhat growing issue as of the past year or so.

PSA: if it’s a cheap led/light from unknown origin or manufacturer, probably best to not purchase it or plug it into your vehicle.

 

After reading through this post and many others Im beginning to second guess swapping out my interior lights to LED's. I have on order from 4Runner Lifestyle Diode Dynamics LED's. From what I understand from others is this is a reputable company with quality LED's.
Any thoughts?

 

As in the other thread about them, just disconnect the battery before changing them out.