[solved] Small electrical issue just got much worse- need help

First time post for a fairly frequent reader. Disappointed it had to be like this. My small issue has now turned into a big issue and I'm at a loss. Hoping someone might be able to diagnose. 2017 1794 Edition.

Went to swap out my OEM fog lights for some Rigid LEDs today. Get everything installed, plugged in the harnesses, hooked the battery back up- turned the headlights on- no fog lights (yes, the switch was on). Headlights work fine. Checked the fog fuse, it was good. Was going to switch the wires in the harnesses to see if it was reverse polarity, but before I did I thought I'd just plug in the OEM lamps to verify that they worked and the problem was just with the LEDs.

Plugged in the OEM fogs, nothing. Pulled out the multimeter to check the fog wiring harness, no power to the fogs. So next thought was to check for power at the fog fuse. Didn't register any, but there wasn't much space and I wasn't really sure the multimeter was making good contact. So I decided to check that by pulling one of the headlight fuses while the headlights were on to see if the multimeter registered power. That's when things got weird.

While the multimeter is touching the contacts where the headlight fuse goes, I hear a beep from inside the truck. The trailer brake output error message is on my dash, as well as a message that BSM is not working. Turned truck off, put the headlight fuse back in the way I found it. When I turned the truck back on, same message. Worse, the truck won't start. Makes a clicking type noise but no turnover. Battery's not dead, plenty of power, and I tried to jump just to be sure.

So I unplugged the battery, let it sit 30 minutes. Turned the key to accessory mode- turn switch to parking lights- no lights come on. Turn to low beams, they turn on, but no drls. High beams work. Switch to auto mode and all lights turn off. (Is this some type of a relay issue?)

With key in on position, the warning lights and messages come back; the lights function the same as above. Still won't start, same noise... Strangest yet, after I take the keys out the ignition, the interior lights flicker on and off almost like a strobe.

Any ideas on what I might have blown here or what I should be trying. Current best plan is get it towed to the dealer before I make it any worse...

 

Pull the relay check it with a meter. As for the fog issue it’s easy to reverse that plug usually it will fit both ways make sure it’s positive to positive neg to neg super easy to mess that up I know I did when I swapped my fogs out I put the plug the way it should fit together it was backwards just rotated it the other way it worked. But everything should be labeled.....check your relay and check the fuses again. Sometimes a fuse may not look blown but can still be bad.

 

Check the main fuse at the battery terminal; that is known to cause some weird electrical gremlins if it is blown or lacks continuity.

 

Thanks for the ideas. Came at it with a fresh set of eyes this morning. Used the multimeter to test all of the fuses with the key in the on position. Registered no power to all 4 15a headlight fuses, and also no power to a 5a fuse labeled "def i/up." Rest of the fuses all work correctly. Visually inspected all of the non-working fuses, and they looked fine. Tried replacing each with the spare from the fuse box, no change. This was with lights in off position.

I turned the low beams on, and retested the headlight fuses. 2 of them have power with low beams on. Flipped the high beams on. All the lights shut off and a clicking noise started from the battery/fuse box area, coupled with a flickering of the interior lights, which stops as soon as I turn lights off.

Same warning lights come on- Trailer Brake/ ABS/ traction control/ BSM.

What's the best way to check the fusible link? I used the multimeter and register same amount of power on both sides of the link, appears to be working. Maybe I just need to replace it and see if that does the trick.

Tried testing the fog light and headlight relays, both appear to be functioning, they click on with power and ohm resistance appears to be right...

Putting some more clues together but still stumped...

 

To me it just sounds like too much stuff going on to be as simple as a fuse. It would stand to reason that somehow The fusible link shorted or got compromised.....Especially with having that many gremlins. I have never replaced one but I am sure others will have experience doing so.

Will the truck at least start now?

 

Negative, but now the battery does appear to be losing power. Disconnected and put the charger on it for now. Going to try replacing fusible link once I can obtain one. Thanks

 

Could it be that your battery has gone bad? Please update.

 

Sure sounds like a bad battery to me...in all the wiring schemes I've been involved in I've had "ghosts" come up and 9 out of 10 times it was a ground issue though.

 

If you haven’t, I’d make sure the battery terminals are good and clean and making a good connection with the battery. I know the terminals on my 18 got fouled pretty quickly.

 

Yep I guess I was assuming that the battery was checked and good. That’s definitely where I would start. Remove it and take it to the auto parts store to test.

 

something is causing a loss of power to the headlight circuit if zero power is registered. The flickering and erratic behavior sounds like a loose connection. Could be fusible link or a ground somewhere.

the no start is likely related in the sense that the headlight circuit probably has to show power before the starter gets power during crank.

 

Reversed polarity, typically on the battery, can blow the fusible link block assembly which is located in the underhood fuse box (See photo). The fusible link block is beige in color, and resides underneath that black housing with the windows (circled in red).

The clear windows in the block assembly allow you to see the fusible link conductors inside. If there is any evidence of burning or discoloration on the windows, or melting of the conductors, then your fusible link is blown. You probably can also use the ohmeter setting on your multimeter to check for continuity across the block assembly; i.e. a reading of "1" means infinite resistance or it's blown. That is also the definitive way to check fuses that may appear to be fine.



Replacing the fusible link block assembly appears to me to be a "beach", but maybe someone with experience will clarify. As far as I can tell, the block assembly would have to come out from the bottom of the fuse box unless that black top cover is removeable).

There are a many Toyota fusible link videos on youTube, and I attach a couple of links for your information. The first video claims a need to drill a hole in the fuse box housing to remove a bus connection screw. Comments on this video say it's not necessary to drill a hole to remove the bus screw, and I can't see Toyota setting it up that way. I think fuse box housing can be separated, but I'll leave that for you to figure out.

The other video is on a 2008-2011 Corolla, and will give you some detail on the way Toyota designs fusible link block assembly installations. Good luck.

https://www.youtube.com/watch?v=XKy0rFOxJnQ&t=72s

https://www.youtube.com/watch?v=P11Kp7MzRjY

 

Great info!

 

Ok. Made some progress, but still having some interesting issues. Took the battery out yesterday, put it on the charger all day. Disassembled the fuse box and pulled out the fusible link (hard to describe how much of a major pain in the . Fusible link was visually intact. Use the multimeter to test 0 ohm resistance between the power lead and all of the terminals, leading me to believe fusible link is fine.

So I reassembled the whole thing (turned out to be a lot easier than disassembling). Put the battery back on, made sure we had good, clean, tight connections. Truck starts right up, no more error messages.

However these electrical issues remain:

Parking lights do not come on, whether truck is running or not.
Fog lights do not come on. Checked the power at the fuse, it has power. But no power at the wiring harness. To test, I tried to hook up the old foglights, which I verified were working by hooking up some leads and putting on a 12v battery.
LED DRL's come on only when the truck is running (my recollection is that they are supposed to turn on whenever the lights or parking lights are switched on). When running, I have DRLs if switch set to parking lights or headlights are on.

Headlights (low and high beam) appear to function normally. But when testing the fuses using the multimeter, the low beam fuses show no power until the lights are switched on. Switch the lights on, the fuse registers 12v. Same with high-beam, no power registered until high beams are turned on.

I tested each fuse in the fuse box with the truck on. There is a 5A fuse labeled D/In near the front driver's side corner that also does not register power.

So other than the above, truck runs again with no error messages. I tested the headlight, DRL, and fog light relays and all appeared to be working correctly (heard the click, and the other 2 pins register no resistance with power to the circuit). Still seems like it could be a relay issue. Trying to figure out how I have power at the fog light fuse, but not at the harness where you connect the fog light...

Regardless, at least now if I have to take it to the dealer, I can drive there.

Thanks for all help and suggestions so far!

 

This is great info, those are the exact videos I watched to do this. Its the same as the Corolla fusible link. Still hard to describe how much of a PITA getting that fusible link out was. Took lots of breaks, photos, and made sure to mark which wires were at which terminals. Made the reassembly much easier. Not sure why Toyota decided to put the piece of black plastic on top of it, makes it almost impossible to inspect without disassembling.

 

I still think that battery is no bueno. Just because you've got enough juice to crank doesn't mean it's got enough sustainable power to run all of your electrical components plus the fact that you had to put it on a charger for the truck to finally start (and eliminate the warning lights) says something.

If you did have a case of reversed polarity, could that cause a short in the harness from the fuse to the fog light? I mean one would think the fuse should blow but electrical gremlins do the uncommon...

 

Put a new battery in today, same issues with lights. Also realized that whatever setting the lights are on, the tail lights do not illuminate. Brake lights work fine, as do reverse lights.

Apparently the tail light/parking light fuse is under the instrument panel, going to check this next.

 

maybe you fried the light stalk to the left of the steering wheel. happened to me when i put a remote start in my old tacoma. i had high beams but lows, parking, and fogs didnt work. ended up being the stalk, i replaced it and that one fried too. i ended up pulling the remote starter out and got a 3rd stalk and it was fine. the stalks on these trucks are known to go bad, many of us have expienced loss of headlights when using the left turn signal, toyots says its a faulty stalk.

 

I think you may be on to something here. I also have remote start, and the last time I tried to use it I noticed it didn't work, but ended up going to work and forgetting about it. Just tried it, and confirmed remote start does not currently work.

 

i think its the stalk

 

I’m no expert... but I wonder about one thing. Having just been in to this wiring while installing OEM LED headlights and OEM LED fog lights a couple days ago on my 2017 Limited... including tying in to the wire under the dash for the dimming DRL function... the good thing is the wiring isn’t all that complex. Did you install the remote start yourself and/or do you know what wires they tapped in to for that project? If so, is it possible an inline fuse or relay for the remote start is on the same circuit as these lights that’s hidden away someplace? Can’t imagine such a simple project would lead to such a headache. It’s so damn frustrating when this stuff happens tho. Ugh! Have a beer. I’m leaning towards (and hoping) for something simple and when you figure it out it’ll be one of those AH-HA moments we can all learn from. I hope so anyway. I think I’d honestly be getting the OEM fogs back in there and working And then trying the Rigids again after that. At least your battery was disconnected... and now you have a new one.... that rules out a lot right there.

 

Pudge has a good bead on the culprit.

 

@Pudge, that’s nuts man. We’re you ever able to figure out how / why that happened. Was it the remote start or the led’s? Can you run both and not fry the stalk?

 

I have no idea exactly what it was but something to do with the remote starter. It was a 99 Tacoma. The starter tied into the parking lights and somehow fried the stalk, well 2 stalks. No fuses blown somehow. Once I disconnected the starter it was all good. I assume some kind of power surge?

 

Can you get a wiring diagram? You can back track and see where the problem is. It's almost impossible to figure out problems like this without a wiring diagram. Kind of like driving across country without a map.

 

GPS works lol.

 

Solved! 15A tail light fuse under the dash in the instrument panel was blown. Apparently this fuse also controls parking lights. Replaced, and everything is back to normal. I had no idea the tail-light fuse would affect function of both the fogs and LED DRL's, as both have their own fuses. Also kind of surprised that with it blown, the "auto" position on the light stalk wouldn't work. Did not check the under dash fuses originally because it didn't seem like any of the issues I was having were related to the problems I was having.

Here's a helpful link I found explaining all of the functions of each fuse in the truck, if anyone finds themselves in a similar position: https://imgvehicle.com/toyota/tundra-ii/fuse-box#

Can't really explain why all the trailer brake/vsc/abs warning lights came on, but it started when I pulled one of the headlight fuses while the headlights were engaged. And as far as not starting, also not really sure. Possible that battery had just drained, or some internal control prevented it from starting while all the warning lights were on.

Remote start still does not work. Its a factory unit, and was installed before I bought it, but I'm second owner so could have been the guy before me. Going to tackle that problem some other day, its been a rough couple of days trying to figure this out and I'm pretty pumped to have full function again. BTW, loving the Rigid LED fogs.

Thanks everyone for help and suggestions, its was very much appreciated!

Its time for that beer!

 

Dude that's awesome!!!! Glad its fixed

 

You were right! He got his gps out and it led him right to the fuse.

 

Someday, somewhere, some Tundra guy is going to install Rigid fogs and blow that same fuse. And instead of spending two days chasing the issue he’s going to see this thread and say “thank God for tundras.com!” Glad you found the culprit and have your Tundra back 100%.