What Could Possibly Go Wrong? Luckily It Wasn't Worse! 

Note to self. If a fuse won't come out, look for a mounting bolt underneath before reaching for tools that chowder the box. That's another little pearl of wisdom that separates the pro from the dilettante.

You were lucky it wasn't a shorted voltage regulator failing to shut off the alternator before trying to blow that 100 amp main fuse and starting an electrical fire. You should have put in a lower amp fuse than called for and maintained protection at some marginal level. A blown 60 amp fuse is better than a 100 amp no blow when there is an active situation mounting.

I thought that everyone knew that if you hook a battery up backwards that the horn sucks and the lights cast shadows. 🤪

Hello Kenny😁one time I had a call in the wrecker for a jump start. It was nosed in a garage and kinda dark. I saw the red and black wires and hooked up my jump pack! Nothing happened. Then , smoke from the fire wall😮I disconnected and then the guy told me the colors were backwards because he ran out of wire or something. Ever since then I look for the bigger post and make sure. I learned something that day. Don't trust anyone

All that for the want of a couple of inches of red electrical tape. Folks, if you don''t have red on your positive cables get some tape and tape them red. I've got a fairly new motor home that had the same issue. I bought some red electrical tape. It's an easy solution to a potentially serious problem. Keep the good stuff coming Kenny.

Great job and thanks for the O2 sensor wire tips. Long live the King Bologna!!!

This made me laugh when I think of the times when I have had fun with my family members who know nothing about cars and needed a jump and I put the red jumpers on the negative and the black on positive. They always threw a fit until I explained to them that colors don't matter just make sure you have + to + and ground to ground and your fine.

Get a jump pack with lithium ion battery... Has integrated circuit that will not allow you to power up if hook on backwards ( some will also beep at you for doing it incorrectly). Saves electronics for the vehicles in today's intermingle modules

You are one of the greatest, Automobile repairman. Just awesome 😎👍

Master of electrical logic/possibilities!! Owner should be very grateful. great, fast analysis!

Thank You for sharing this video with us. I learned a lot about the fuse box and screw in fuses. Thanks again! Much Love and Hugs

I love the expression, "Let's see what I can't find here". Kenny, you are mixing up your terminal .. ology! Be positive .. "Let's see what I can find here".

A good example of fuses doing their job!

Good evening Mr Kenny and happy e😊

Holy crap, almost same exact model/color i had before someone rear ended me! Miss this truck!

My dad insisted on "helping" jump start my Escort. He hooked up the end to his car reverse. It cooked several wires on my car and fried the alternator.

Kenny that was a permanent master fuse. When it blows you replace the truck…..

It surprised me that it didn't fritz the wholw fuse box & alternator .I also amazes me that people fu the cables when trying to jump start a vehicle .THE BIG LESSON HERE IS CARRY A JUMP BOX IN YOUR CAR IT HAS INSTRUCTIONS ON IT ON HOW TO USE IT WHEY ARE NOT EXPENSIVE. Cheers Kenny.

Been there, done that. Wife yapping in my ear. Distracted me and I crossed the jumper cables on a 91 Mitsubishi pickup. Blew the fuse and saved the PCM. Boy was I glad that was all it did!

Thank s

I would also check for excessive current drain in case one of the alternator diodes is leaking after the reverse jump.

Just creating some interaction here, seems youtube likes that. Thanks from The Netherlands for the effort to video your work. Red tape the positif battery terminal cable?

fuses protect wires from burning up. I'm surprised you didn't tell them to bring it back to replace 100 amp fuse with the correct 80 amp later when you can get one in stock?

Kenny do them a favor and spray paint the positive terminal red. That is what I do.

Thanks! The only other time I've seen them blow besides being reverse boosted is with a seized engine or pully.

As in your title, luckily it wasn't worse. Nice job, and troubleshooting.

Toyota of that era has a reverse polarity diode in the feed to the ECU, which can also be blown open circuit. Normally in the fuse box as well as a plug in module.

I appreciate this video "Little Kenny". I learned about the fuses that have a screw in base. Prior to this video I didn't know about those.

Fifty-plus years ago my dad thought the battery was dead on one of our cars. He jumped the battery and there was a loud bang! He had misguessed that the battery was dead. He had also connected the jumper cables backward. The battery he was jumping actually blow up!

That wire at 13:22 is a fuse tap or add-a-circuit to power something aftermarket usually. Writing this I am thinking you knew that but meant you didn't know what it was powering.

Yes I’m confident you know your diagnosis skills . Thanks for sharing your video info.

Wow , never saw this before

I would have wrapped a piece of red electrical tape around the positive wire. Solve the root problem too.

Great video and simple step by step..Eliminate small stuff 1st…Have the customer pick up a red terminal cover for the positive post or som red duct tape also works as simple reminder…. Thx Mr Kenny from Wetmore Colorado….

Some times if I have to start a bolt in a tight spot l put 8 peace of paper in my socket so the bolt stays tight on the wrench.

Went to jump start a friends car he received from a family member handed him the cables and he was standing there looking at the car, I says what ya waiting for he says it had two red wires. I look and sure enough both cables are red!!! Learned a lesson then LOOK AT BATTERY PLUS AND MINUS NOT CABLE COLOR!!!!!

What was I hearing when you connected that rogue wire up to the fuse block? On all the time?

Yelp I learned a new one have seen many of these fuses never knew they were bolted in so now I know I've not had a bad one of these fuses either .

Seen many of those Kenny. People jumping them backwards and blowing out the master fuse. Now they on the hunt for it. Some vehicle have a master battery fuse. It's expensive tho.

Good catch Kenny, it would have been nice if they would have maybe told you that they had done that. But then again they probably didn't realize they crossed the wires or blowed the fuss.

Owner not paying attention! But I recall other higher end Toyota vehicles with "drive by wire," the ECTS fuse would blow. Throttle will not rev up.🤷🏼‍♂️

Regular cab and bench seat. My aching back...

Bolted in fuse?! Seems to be vast overkill. Hard to believe that reverse polarity didn't take out more modules and computers.

After it ran for a couple of minutes, it sounded like something under the hood was starting to squeak, hopefully you don’t have a pulley fixing to seize.

Great video Kenny.

My RV used to have two black battery cables. I put RED electrical tape on the + cable.

Replacing an 80A fuse with a 100A fuse. What could go wrong there.....And what a way to mount a fuse in there, Who would ever think there was a bolt hidden that has to be removed. Crazy stuff...

Great Stuff Kenny ... great content

I would have dropped those little screws for sure 😂

Another great job

Reversed connections can blow out the voltage regulator, and more.

I think it is possible do this job without removing the fuse box. Remove the battery only and you have lot of space. When the fuse box is securely in place it is easier to screw the fuse bolts.

Good video!

Kenny, I've only watched a few of your videos so far and I'm sorry but as a fellow tech, I'm disappointed in your decision to use a 100 amp fuse instead of the correct 80 amp one. I understand that there is a very good chance that NOTHING will ever happen to this vehicle even though you used the incorrect fuse. However, you should know better of the "possibilities" of what "might" happen should there be an "oops" moment in the future. Also, given that this is one of the larger fuses if not THE largest fuse, I don't think it's a good idea to use this instead of the correct fuse given that the could be catastrophic should the fuse not blow when there is an issue with the wiring, alternator, or combination of other things. This isn't like putting a 15 amp fuse where a 10 amp should go or a 30 amp where a 25 or even a 20 amp should go. In "most" cases, those other smaller fuses are handling smaller loads between components and in those cases, if you have a wire that gets melted, it's likely not going to cause a more major problem like this larger 80 amp wiring may cause should something go wrong. Sure, there are a few here and there that wouldn't be that great to fix but I would bet that in most cases, the larger amperage wiring would be a bigger problem to correct. Another thing that I think you're maybe not considering or at least didn't mention in the video (that I noticed) is that since this whole issue likely started due to improper usage of jumper cables, don't you think that there's a pretty good chance that either the owner or whomever they have help them work on their car doesn't know what the heck they are doing when it comes to simple things like jump starting a car? And as such, given that this 80 amp fuse is a pretty damn important one to keep in tact to properly handle the load of that circuit for the vehicle to operate properly, don't you think it would be a good idea to put the correct one in so whomever decides to have another "oops" moment in the future doesn't screw something up again? I understand that you didn't put in a fuse that was double the power handling such as a 160 amp (I'm not sure that they would even make one that would fit that anyway) or even a 140 or 120 amp fuse, but still, an extra 20 amps might be all that it needs to have a problem. I read another comment where they mentioned the same thing I was thinking and I'll repeat it here. It would be one thing to use that 100 amp fuse to get them "back on the road" but at the very least, you should put the correct fuse back in when the parts store can get one in stock or you can just order one online. Another thing to consider is that you have got a decent amount of viewers watching your videos and I don't think it's a good idea to say something along the lines of "that should work" or "it will be fine" when it comes to something like this. Again, I understand that this isn't a 160 amp fuse in place of this 80 amp fuse. I "get" that only an extra 20 amps will likely be okay. But remember why it is in your shop in the first place. It's likely because someone made an "oops" moment come to life and caused this problem. Not good. If this was your own vehicle, then it would be different. I'm not trying to make this an "end of the world" type of criticism. It's not that. But I think you should get the right fuse in place so it's correct. After all, if the circuit was designed to handle a 100 amp load or higher, the engineers of this vehicle would have put a 100 amp or higher fuse in place to handle that type of load. In spite of this, your vids are pretty decent so far for the few I've watched.

I did that to my chevy Colorado. It blew the 100 amp mega fuse. similar symptom to a blown alternator. I made a jumper with a 40 amp thermal circuit breaker and limped back home.

I have seen a half dozen toy s blow that alt circuit and main fuse if they are hooked up bacwards. Its a pain to take the fuse box oùt but not as bad as frying the pcm

i wish he woulda unplugged the battery first. just tugging on whats left of that fuse with it all still hooked up. yikers.

I've always warned my kids. Don't jump a vehicle with your car. You may kill your car too or damage the other person's vehicle.

what is the wire thats dangling off the exhaust at 15.07 ?

Sooo that's how those fuses come out... Cornhole Sad a nice Toyota truck sitting for years due to two bad fuses. Some one bought that one cheap and it's a Manuel...

12-volt batteries positive post is always fatter than the negative post. Also look for plus sign on the battery.

Maybe paint red on pos terminal wire?

Great fix.

I did that once and burnt a alternator. I couldn't read the terminal in a dark situation.

Regrets build character..

Quick look at the Walmart Maxx series batteries... Great 3 year replacement warranty & sometimes they'll go off the date production code if you lose the receipt. 4/23 so made in April 2023

Would a lesson taken from electrical circuits help this situation? Im talking about a bridge circuit with 4 diodes in a pattern made to direct voltage only to the positive or negative terminal regardless of hookup

Your results are high, because you do not test with the cable's on your said cable's attached to the battery cable's

Can You Add That Battery Tester To Your List So I Can Locate One Thank You

The new snapon needle nose would of not slip.

Get the correct fuse 80Amp

This is a good example of how well engineered Toyotas are . the fuses protected the Alternator and the E.C.M. If that was a FORD you would be replacing the E.C.M and the Alternator nice job Kenny

bad idea fitting a 100 amp fuse where there should be an 80 amp fuse

just to play devils advocate at 15:05 you say the WIRING comes disconnected ie the plug then there wouldnt be any puwer ground or sensor return connected but if a single wire brakes free and finds power or ground or the sensor cable is too long and gets burnt through by being too close to exhaust will blow fuse

Very lucky all the modules are not Kaput. Must have protection. Looks like it did from the comments.

Was common on old 6 volt cars some were pos. ground others neg. ground.

And at least on older vehicles hooking up a battery backwards can damage the alternator.

Years and years ago i had just smoked a big fattie and had to jump start my buddies truck w my 97 ranger well wouldn't you know i hooked them up backwards and took out the alternator that quick i guess those old fords didn't have main fuses like that back then to protect it or its possible its because the truck was running at the time i connected the cables i knew something was wrong in seconds like the saying goes at that moment he knew he fucked up ! Lol

A blown 80 amp fuse sounds like a lot of heat...and melting...

Ive seen a girl blow the whole front end of her car by trying to jump her car backwards. It was on youtube

Note always pull ALL fuses before junking a car.

Never give anyone a jump,...ever However it's ok to receive one.......

👎👎🤬🤬 Extremely disappointed in you on this one! NEVER EVER PLACE A HIGHER AMP FUSE AND LEAVE IT IN PLACE. You may have created a very unsafe condition even if you believe that you think the reason for the 80 amp fuse blown was caused by reverse connection jump starting!

Dissapointed... you started pulling on the fuse before disconnecting the battery..dork!