10a Gauge Fuse Keeps Blowing After Certain Amount of Time on The Road.

This is my last hope, I don't have enough money to take it to a shop right now so I'm using my buddy's house and his tools to try and diagnose this to no avail.

I have a 1st Gen Tacoma, 2002, bought it around 8 months ago and it's treated me amazingly. Besides some check engine lights with old sensors of course. But recently, I took it up one of my favorite places to offroad, and I might've beaten it up a little too bad trying to race my buddy up the mountain. I don't know when, but I was taking it up the hill in my normal street mode just 2WD, keep in mind I'm not looking at my gauge cluster I'm just focusing on not getting my tires screwed up on the rocky road, but when I make it to the top of the hill I look at my gauges and they're all off. My transmission temp, RPMs, and MPHs are all down. My gas gauge shows how much I had in my tank at the time. The only thing I can see on my dash is the RR DIFF LOCK light, and it's flashing. I found out later on that I don't even have a Rear Diff Lock on this truck, a mechanic dude I met looked at it and he said I don't have the correct thing on my rear diff to have it lock.

However, where my rear diff lock button SHOULD be, is a little button, it has a little light in it that lights up that shows me I have power, but I believe it's an alarm. The guy I bought this truck from was from El Salvador and then Oakland, and he told me he had alarms installed and whatnot, I don't know everything. But all of this is controlled by the circuit with the 10a GAUGE fuse. It popped going up that mountain. I'm not good with wiring, but this gauge fuse pops every time I drive it. It'll work for a little bit, and then after a while it'll just blow and my gauges all fall down to 0.

I thought it was my alternator, I took it out and took it to get tested for free and the guy said it was fine, I tested my battery and it was completely destroyed beyond repair, I used my warranty to get a new one and ever since then my truck has been sitting untouched, I took the battery completely out as to not have it get drained just in case.

I'm stuck, the truck died on me while driving it, that's why I thought it was my alternator, it wasn't, my battery got drained somehow and something is shorting my circuit to pop that fuse, I'll attach images below of that little red button light and I'll also attach a couple images of these red wire things that mechanic guy told me were aftermarket, and I'll show my terminals too. This could all be a grounding problem? I don't know, at this point I'll take any advice I can receive.

 

That light and wiring is definitely for an aftermarket alarm system.

Is the amount of time it takes the fuse to blow consistent or does it seem to be random?

Since you said this started happening while offroading I'd suspect a wire shorting to ground, the Gauge fuse does power the ignition circuit in the alternator and also the Vehicle Speed Sensor on the transfer case so that would be some areas to check wiring.

How I would find a short is put a headlight bulb in place of the fuse, when the bulb goes bright I'd start unplugging things and wiggling wires while watching for the bulb to go out or flicker.

Like in the video below.
https://youtu.be/oKCLzf4va7M

 

Just looking at diagrams and the Gauge fuse powers alot of stuff.

Reverse lights
Alternator IG Terminal
Vehicle Speed Sensor
Combination Meter (Instrument Cluster)
Transmission Range Switch
A/C Controls
Daytime Running Light Relay (w Daytime Running Lights only)

 

Awesome omg thanks a ton man, I'll get into that tomorrow, it seems to blow pretty consistently, like every 15 or so minutes. I got a Check Engine Light when I first replaced that fuse and I took it to O'Reillys because at the time I didn't have my trusty OBDII scanner, and it flashed with a "Vehicle Speed Sensor A" code P0500, and I replaced it, it was this little black piece that went on the transmission, I don't remember it being the transfer case but I could be mistaken, are the Transmission Speed Sensor and the Vehicle Speed Sensor the same? Either way, I replaced the Transmission Speed Sensor, and the code went away, and won't show up in the OBD scanner. That could be my problem, I also recently got a new starter and maybe something wasn't plugged in all the way or something. It's currently 1:30 am right now so I'll get on it tomorrow thanks man

 

Had some bad luck strike again. I did what the video said, unplugged everything the circuit was connected to and the light stayed on, so I plugged everything back in and then I also cleaned a very dirty ground wire that is below the oil filter on the engine. Boom, truck worked, AC worked, I drove it around for a couple days and everything was fine. I didn't blow a fuse and nothing came up I don't have any CELs, and then just out of the blue the fuse blew again a day or 2 after the unplugging and replugging. Here's some pics and a Pic of that ground wire. I just want to know where the VSS is, because I found the TSS, and I don't think they're the same thing but I'm getting 0MPH on the OBD scanner while I drive it when the fuse is popped. I think the VSS is blown and it's drawing too much power. In order to survive I need this truck running so I want to just unplug the VSS so I don't get MPHs on my dash but as long as it's not chewing through my battery power I don't mind.

 

Interesting, seems you still had a short somewhere in the wiring if you had everything unhooked.

The VSS should be mounted on the tail housing of the Transfer Case.

 

I unplugged it, along with other things I can get to at this moment, I'm not at the house I need to be at with tools I'm at a different house and now it's blowing fuses as soon as I turn the truck on, isn't good. I'm just gonna have to drive it back to it's original location with this happening, it's gonna drain the hell out of my battery but I don't have any other options, it's blowing the fuses as soon as I turn the key

 

This sounds like a really shitty situation. Electrical gremlins are a pain at the best of times, and your situation sounds less than ideal.

As soon as I started scrolling through your pics of the wiring and saw the taps and electrical tape, I literally said to myself "Oh no, the mark of the beast."

I am not super familiar with the first gen trucks, so I can't offer you any extremely specific guidance, but I would at a minimum remove all of the non-factory wiring that you can find as a starting point. There is no telling what connections might be flaky, what got cross-wired, and so forth without spending a heck of a lot of time with a meter and possibly a scope hoping to replicate something that only seems to occur while driving. Maybe you get lucky and the problem is solved, but at a minimum you reduce the amount of stuff you have to spend a heck of a lot more time/money/attention on if the problem lies elsewhere and you need to start hardcore diagnosing.

 

Yeah I'm thinking under my dash is where the problem is, I can't find a short in any of the wiring in or around my wire cluster. It just sucks it happened recently and not a while ago when I had the money to take it to a shop. I'm gonna unplug that alarm system, which by the way I forgot to take pictures of but it doesn't even have a brand on it, it just says "Made In The USA". I don't even have a siren in my engine bay I don't even need this random thing that could maybe be sucking all my power in my instrument cluster.

 

Shorts can be difficult to track town especially when they are intermittent, being you have a constant short makes it easier.

I've found that most of the time shorts that blow fuses are more often a wire rubbing on something than a component and it's typically exterior wiring, interior wiring shorts are typically man made.

Visual inspection of wiring harness goes a long way in finding shorts, any place a harness contacts something metal like a bracket or pipe is suspect. If you leave your test light hooked up you can also wiggle on harnesses while watching for the light to flicker or go out indicating you are in the right area.

A clamp on DC ammeter can be helpful as well because you can isolate individual branches of the circuit and find out where the current is going then focus on that branch.

 

That makes enough sense, I was looking at my wiring harness earlier and couldn't see anything but I'm definitely gonna look at it again. I'm returning to my home town to start work and it's a 2 hour drive, hopefully it doesn't die on me. I drove it from that one house to the original house I was at, like a 20 minute drive, and the whole time I had an OBD scanner hooked up to check my voltage and it'd stay at 12.1V for a while and then flicker between 12.1 and 12.0, and when I rolled my window down, turned a blinker on, or plugged my little alpine radio head unit thing in, it would dip down to 11.9V. I've come to learn if I want the most out of this battery I can't have anything electric draining it so I can make it home. My alternator isn't even recharging it which fuckin sucks. It's just sloooowwllyy draining it

 

Dude I just found out my reverse lights don't work, and that is the same circuit as that fuse. I'm gonna look into that but that could really be it.

 

Nevermind that was my bad, of course the reverse lights don't work, my running lights and everything else on that fuse doesn't work. I'm gonna start inspection from front to back and if I can't find anything I'm gonna cut my losses and take it to a shop when I get some money in my pocket.

 

My 2003 taco is also having the same issue. The first time it ever happened was in 2019 when I accidentally shifted to L then the 10A fuse blew and I drove it like that for like a week which caused the battery to drain and die. Got a new battery changed the fuse and then I was off with it. Two years ago the fuse blew again changed it then I was good until like a week ago when it blew again now after changing the fuse every time I drive over a bump or pothole it triggers it back to where it turns on the rr diff lock light and nothing working besides the gas gauge.

 

Osvaldo, it really sucks doesn't it. Yeah I took it to a shop a week or 2 ago and I had the guy install this circuit breaker thing on the fuse so before it pops the breaker just disconnects and it acts like the fuse blew, and then when it cools off it powers all my stuff back on. I had it break only once and it was on the way back from the mechanic. Ever since then it's treated me fine. Now I'm having some engine misfire codes show up, this shit never ends.

 

My 05 rav 4 had similar problem with the 10 amp fuse .I had installed 10 amp circuit breaker in place of fuse and after 10 months finally found short in wires going to alternator . wires were chaffed but couldnt see because the 4 wires was together like how you see in your picture I got circled . That was (mine) the 1st wires I checked because plastic wrap was torn but looked fine .On bottom was chaffed and 2 wires were shorting out . Only found because short was getting worst and when shaking wires was able to pin point . When checked under wire was like fck . Was one of the first wires I checked but didnt check good enough.

 

This was my short. Took me 2-3 weeks to find it throwing all my electoral gear at it. Finally found it with a home made connection to an H11 bulb. Super fun. Hang in there, don't beat yourself up.





https://youtu.be/qSvTksadxiw?si=GEpBc4I8UJWmwU5i

 

It may only be a 20% chance that is causing it, but if I were in that situation I think I would remove the alarm and make sure all the connections or wire any taps from the install/removal were sealed up.

Around here they aren’t as popular as back in the day, but the quality of the install was always a bigger difference than the quality of the alarm brand when it came to electrical issues.

 

Mr. Boi64 I took my truck to the shop about a week ago and turns out my 10a gauge fuse was shorting because the L or 1st gear wire that’s in the harness going through and under the intake manifold was melting making the wire more exposed over time and until recently making the fuse blow consistently. I forgot to mention also having a P0500 code for VSS right before getting it fixed and since the wire being shorted goes all the way down to the transmission it was giving me that code. Will post post pictures when I’m back in town.