Lesson on fuse ratings

[TheBarber]

Perusing my photos and came across this gem. Remember, when your fuse keeps blowing, you should probably figure out why. This gentleman decided to "upgrade" this 10a circuit to 30a with one little trick technicians don't want you to know!

Enhance! MMMMM, toasty!

Obligatory stereo wiring complete with a cluster of black oxide sheet metal "ground" screws.

Finally, this is probably the point of realization that maybe he did a whoopsie.

This was on a Honda Ridgeline. Craptastic aftermarket trailer light controller piggybacked into taillights failed internally (like they always tend to do). So instead of figuring out why his 10a external light circuit fuse kept popping he sticks in a 30a fuse in its place. Wire for shorted circuit then proceeds to hot-wire through floor harness. Best I can tell it hit the yaw cluster wiring for the SRS system and caused erroneous data and SRS unit thought it was rolling so it blew the side airbags. Hard to say for sure as I cant access that level of data from the control unit.

Floor harness, bed harness, side airbags, srs control unit, seat belt pre-tensioners, and went ahead and installed the genuine accessory trailer control unit for him. Right as rain and lesson learned.

PS in case anyone was curious what a Ridgeline looks like bedless.

[LooseonExit]

@thebarber

That's the most damage I've ever seen done with an oversized fuse. Excellent work on his part.

[flatisflat]

[Note to Self: be mindful of aftermarket piggyback trailer taillight control module installed in your MINI. Do not set off airbags.]

[Exage03040]

"Amateurs don't use up rated fuses. I've seen the way you wire, you've got a heavy crimp, you'll fry yourself to pieces."

[TheBarber]

@flatisflat To be fair I've probably pulled out only a dozen or so over the past decade. Usually worst case scenario is you have no exterior running or brake lights. Which, you know, isn't great but it's better than this. They were all unbranded and all installed from U-Haul. So, YMMV.

[TheBarber]

@exage03040 Wow... Bravo. It's a very specific adaptation but soooo good.

[Shop-Teacher]

@thebarber That is an expensive lesson!

[Rusty Vandura]

@TheBarber @Exage03040 @Shop-Teacher

Real men just wrap the old fuse in tin foil.

[TheBarber]

@rusty-vandura Ha! Or a paperclip. I have used some spare wire to jump 100a mains more than once. But I knew why they blew. Damn kids jumping cars backwards.

So what happened here was you went with the heavy duty reynolds foil when you should of done the standard. Pfft, amatuer.

[Urambo Tauro]

30 amps? Those are rookie numbers!

[Exage03040]

@rusty-vandura said in Lesson on fuse ratings:

@TheBarber @Exage03040 @Shop-Teacher

Real men just wrap the old fuse in tin foil.

I'm real old school: copper penny.

[VincentMalamute]

@TheBarber I made tail/brake/turn lights for my bike hitch rack. I dreaded running a power line from the battery all the way to the back of the minivan. My buddy, the Jeep guy, told me to just take power off the minivan tailights for the trailer hitch controller I installed to run the lights. Thank you for showing why I didn't do that.

I did take the easy way out and ran the power from the battery underneath the minivan and then poked it through the into the minivan at the back. That airbag is hilarious!

[TheBarber]

@vincentmalamute Hey, as long as its fused at the power source you're good to go. I've had an unprotected power wire at the battery slice through a plastic brake master cylinder reservoir when it shorted on the firewall. They decided to drill through the firewall and not use a grommet or secure it anywhere. Came in for a plastic burning smell. I see that a lot though. I am also not surprised when I see so many cars fires.

Pulling from available power somewhere isn't bad per say. You just have to use a bit of common sense. Could you pull and extra amp from an existing circuit to power some accessory LED's on an older car? Sure, but if you pull more and blow a fuse just make sure you put the correct rated one back in and reassess your circuit. Modern cars can get a bit weird when pulling from some circuits. They definitely get weird if you are hooking up some cheap controller and get backfeeding into a control unit.

Takeaway:
Biggest thing is make sure whatever power you run is that it is protected at or near the battery. Proper rated in-line fuses are your friends.

Edit:
What bike rack is that? It looks well built. I was thinking about getting a top one for the Tahoe but alas my other half is short lol. So I'll probably get a hitch mounted one.

[VincentMalamute]

@TheBarber Thanks for expanding on the cheap controller issues. I wasn't aware of that and backfeeding. I got a Tekonsha which I think is not a cheap controller.

I calculated the amp draw of incandescent trailer lights if I hooked up a trailer and the amp draw was too close to the fuse rating of the Sienna's tailight circuit for my taste. If it's just the hitch rack lights, the taillight circuit had plenty of current headroom.

I used the Tekonsha wiring harness which included the very long power lead to the battery. Yup, they included an inline fuse on the wire at the battery.

The bike rack is 1UP. It's very nice and expensive. No plastic or rubber anywhere. I did the rooftop mount thing and tired of it. Not to mention ramming my bike into my garage once. The folding arms clamp onto the tires and it's much easier to use than my friend's rack with the vertical pasts that hold down the frame.

[Highlander]

@thebarber So how much did that run? It looks like it might be extremely expensive.

[Darkbrador]

@vincentmalamute said in Lesson on fuse ratings:

bike hitch rack

I read that part too fast ...

[Tripper]

@thebarber Wowzers. Last summer my FIL hooked the battery to their boat up backwards. It was also not properly fused and it all came together behind the speedo.

Believe it or not I separated out each wire, and replaced the melty sections. Hooked it all back up and EVERYTHING works. Couldn't believe it.

[Future Next Gen S2000 Owner]

I assumed he stuck a penny or something in the fuse box. That must have been an expensive fix.

[TheBarber]

@highlander It was somewhere in the $2- almost 3K range I'm sure. I fixed this one 6-7 years ago so price is a little fuzzy. But carpet, headliner and bed removal labor alone was probably close to $2k. The cost to his ego I'm sure was priceless.

[TheBarber]

@tripper Impressive! He certainly got lucky with that one. I admit in my greener years I may have done a few dumbs on battery installs. Main fuses are a lifesaver.

I had a friend in Co. Springs working on a newer CR-V that had been struck on the pass side mirror by lightning. Everything got fried. No fuse will save you there.

[TheBarber]

@future-next-gen-s2000-owner I returned his 30A fuse to him taped to his repair order as a nice reminder. Although I'm sure he didn't forget the lesson after paying his bill.

[Future Next Gen S2000 Owner]

@thebarber That's awful kind of you. Saving him the few bucks of a new 30A fuse to install at a later date.

[TheBarber]

@future-next-gen-s2000-owner Gave him the ol' catch and release. Haha, naw It was already popped. I think it finally met its match when the circuit hit direct body ground. There was some fried bits of wire behind the left taillight that I had to scrape off the body.