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Fuse issue or fuse box issue

In the 25 years or so since I’ve owned my truck, occasionally I’ve run into a problem where ill be driving and my truck will die. as in lose power and the engine shuts off. i did some research maybe 15 years ago and found that one of my fuses was burning out, i was in a hurry and changed the fuse…problem solved. however this happens very intermittently, but this last Saturday night my wife arrived at work and the truck died. she replaced the fuse and the truck started immediately and continued to drive until this morning when the truck died again. we will change the fuse again and buy new fuses as the ones in our ashtray are probably 13yrs old. any ideas why this is happening, is this a sign of a bad fuse box or a going fuse box? can fuses go bad if left sitting in a metal ashtray. keep in mind the last time the truck died before Saturday night was over three years ago. - short circuited in Florida

I don’t think you understand what fuses do. When a circuit draws more power than the wiring can safely handle, the fuse goes out to protect the rest of the circuit. You need to figure out what’s drawing too much power on that circuit, whether it’s a short-circuit to ground in the wiring or a device on the circuit that’s malfunctioning.

If you tell us what circuit this is, you might get better help.


Agree. Something is causing too much of a power draw. Bad wire, connection, short someplace, computer going south etc. I’m assuming the circuit is for the ECM computer or I suppose it could be for the fuel pump which would mean the pump, relay, wiring, connection, is going south. Not sure what else besides those two would shut the vehicle off.

When 1 of my fuses kept blowing, I cut every wire in the circuit, 1 by 1, until I found the culprit: the wire that supplies power to the glove compartment light. My truck doesn’t have a light in the glove compartment. The Toyota Forerunner (a kind of fake pickup for sissies) did, and shared the same wiring harness. Unfortunately my ohmmeter reads no lower than 1 ohm, less than the expected resistance of a 12-volt circuit rated at 15 amps.

Do you know which circuit that fuse is for? If the fuse is in the circuit which supplies power to an electric fuel pump, it’s possible the fuel pump is starting to fail and drawing more and more current. Or the fuel filter is plugging up. Another idea, fuses can overheat and blow, even tho the current is within proper range for the circuit, if the resistance at the interface of the fuse and the fuse holder gets too high. Try cleaning those two interfaces (at each end of the fuse, and where the fuse plugs in on the fuse holder) of oxidation.

I suppose you think you’re pretty clever for calling it a “ForeRunner” instead of the proper name, which is 4Runner . . . ?

So you apparently don’t feel your Toyota truck is for “sissies” . . . I’m guessing you have a Tacoma, since that’s the one that shares some mechanicals with the 4Runner. So you don’t have Toyota’s largest truck, the Tundra

Just remember there’s always going to be somebody with a bigger truck, and he/she might consider YOUR truck to be a “fake pickup for sissies”

YOU are the one that started this

you definitely picked an appropriate screen name


It could be a frayed wire that occasionally touches a metal part that is grounded, or a damaged harness with two frayed wires that touch each other.
It could also be the fuse socket with terminals that are loose or corroded.
The high terminal resistance can generate enough heat to reach the fuse link and make it melt (I seen this happen).

Whoops! You’re right, almost. The Haynes calls it ‘4-Runner’. Sorry. It was an honest mistake.

I diagnose an irony-deficient diet. I share Dan Savage’s opinion of sissies. Next time the Good Humor man drives by, get an ice cream on me.

I have an '87, which is just a ‘pickup’. I don’t know if they made the bigger truck then, which used to be the T-100, before they thought up fruity names for them.

The larger point I wanted to get at, one I Fratelli Magliozzi often made, is people who buy pickup trucks for non-work purposes, either because they aspire to a lifestyle they associate with it (remember those services that would dirty your Jeep/pickup so you could drive it that way to work on Monday?) or because lower tariffs made them relatively cheaper (thus all those fake pickups).

Short circuits can be tricky if the wire isn’t touching metal all the time. There could be a problem with a component on that circuit. Not saying you won’t find it but it could be a wire check or something that is hard to find.

Which fuse is burning out? That’s the first clue to what circuit to look at.
Once you know this, you can if you ask nicely maybe get a print from the Toyota parts window guy of the relevant wiring diagram and schematic (two different things). With these, you can perhaps trace the intermittent short. Usually they’ll be where a wiring harness goes through a relief hole in a body panel, often to a door lock or power window control where the harness is routinely flexed. You’ll probably need to cut the harness insulation and the tie cord, separate out the appropriate wire(s), and splice, tie, and insulate it all back up. Generally when I find such a break in the insulation I cut and install a rubber grommet if none exists. You can get them at the hardware store for about a buck apiece.

But the first step is to use the fuse identification to identify the problem circuit/harness.

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I thought “Forerunner” was a synonym for Prerunner.

Not sure what to make of this unusual truck conversation. Should I be insulted? Or not? … lol … the truck I’ve owned for going on 45 years now, I didn’t buy it for work purposes. I bought it for it 4 wheel drive and high clearance, going camping, going skiing, and the occasional need to move my belongings to another apartment. I’ll admit I did use it for work, in a manner. For driving to my office job when the roads were covered in snow. Oh, I liked the way the CB antenna looked on the truck too! :wink:

Hope that covers it.


George we need a picture of this truck.

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Not gonna happen. My truck likes its privacy.


found the issue. turns out that he fuse box socket for the ECM-Ignition fuse was bad. replaced the whole box and problem is fixed now thanks for all your inpout!!

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Good for you for getting the problem resolved. Yours isn’t the first fuse box replacement positive experience posted here.

You’re welcome.

seems like an odd approach to find a circuit problem. How about just disconnecting associated connectors or using a multimeter and checking for shorts and continuity?