Questions tagged [fuse]

An expendable (single-use) electrical component that safeguards an electrical circuit by melting or otherwise interrupting the flow of current if the current exceeds the designed limit.

A variety of different blade type fuses (Wikipedia)

A fuse is a component often found in electrical systems that acts as a safeguard for the electrical system of a vehicle. The primary purpose is to protect the wiring and components of a vehicle from damage. Typically, automotive fuses have two blade connectors and a plastic housing that contains the conductor which reside in a fuse panel (see the tag). There are other types of fuses, such as fusible links, which are in the wiring itself.

Fuses contain a conductor which is sized in such a way where it has a specific melting point that is lower than the wiring it is connected to. When electrical load is created, which will heat up the wires, any unsafe load cause the conductor to melt, thus interrupting the electrical circuit. Blown fuses must be replaced in order to re-establish the circuit.

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Why don't cars have circuit breakers instead of fuses?

While there are exceptions the majority of cars use fuses instead of circuit breakers to protect electronics and I'm wondering why circuit breakers are not more widely used. Is it practicality, cost, regulations or a combination of those factors?
GdD
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Should I replace fuses as a part of regular maintenance?

I've been having a few problems that might be electrical in my car. Seeing as mechanics always want to replace parts first, I'm having to diagnose this problem myself. It seems like replacing all the fuses would be cheap and preventative, and more…
Betsy Dupuis
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40amp protection on 25amp rated wiring?

Q - why is the circuit described below protected with a 40amp fuse when the cable to the motor is 2mm² (I cut a bit of cable out and measured strand thickness and quantity, 37 * .26mm = 1.98mm²) and therefore likely rated for 25amps max. (All the…
Nathan
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How do you test analogue electrical circuits?

When trying to diagnose problems with conventional analogue electrical circuits, such as lights, speakers, heated rear windows, etc, as well as short-circuits and unexplained current draws, it can be difficult to track down the exact source of the…
Nick C
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How to test a bolted-in heavy duty 50a / 80a / 100a fuse with a multimeter without removing it?

I want to check if this particular 50 amp fuse on a RAV4 (1998 first generation) is blown or not. Just looking, it's hard to tell because of what I assume are blue-green deposits on copper (this is the view inside it with the cover…
user56reinstatemonica8
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How can a fuse drain a car battery?

My car battery drained itself after a week of not being used. I was researching how to identify the cause, and saw a comment under this article saying: What if I am not detecting a reading but the battery still drains? You could have a fuse that is…
user56reinstatemonica8
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Fuse box above battery melting

I have a 2001 VW Beetle which has a nasty habit of melting the above battery high voltage fuse box. I've replaced it three times already and replaced the alternator as well, but I'm at a complete loss as to what's causing the problem. Apparently…
apaul
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How to remove the 50 amp, 80 amp and 100 amp fuses from the positive terminal of a RAV4?

I want to check the fuses at the positive battery connection of my 1998 (first generation) Toyota RAV4. Visually, the 80a and 100a look fine, but the 50a has blue deposits and I can't tell if it's broken or not. No power is reaching my engine…
user56reinstatemonica8
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Indicators Not Working But Hazard Lights Working

Vehicle: Mitsubishi Pajero 1994 I have a 1994 Pajero and had a strange problem happen this morning, in the middle of driving the indicators strangely stopped working but when I pulled up the hazard lights where working.
Chris Rutherfurd
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Preventing Car Theft by Removing Fuses

My car was recently stolen in the middle of the night, and I just bought a replacement. I'd like a simple, cheap way of disabling the vehicle, and I was thinking of doing something like just pulling the fuel pump fuse out every night. However, I…
Robert S. Barnes
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Cigarette lighter fuse repeatedly blows

I have a 2000 Toyota Corolla. Recently, the fuse for the cigarette lighter blew when I put in a car charger. The fuse powers the cigarette lighter as well as the radio and I think the backlighting on the air conditioner panel. I tried replacing the…
Daniel
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Does a constant blown fuse always indicate a short?

My wife was driving our 96 Ford Windstar recently and she said right after she hit a bump in the road the ac stopped working and the instrument panel lights went out. I found the fuse from the wiring diagram and replaced it bringing the instrument…
James-Jesse Drinkard
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Seat heater fuse at 12V even when ignition is off?

I'm looking for a fuse in my 2015 Honda Odyssey that is 0v when ignition is off. I thought the passenger side seat heater should be the one but I tested 12 V when ignition is off. Is this normal?
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Radio and Charging Outlet Stopped Working

I have a 2000 Honda Accord V6 LX. The radio was working yesterday and the charging outlet was working earlier today, but now neither are. Did some research and I'm assuming it could be a blown fuse. Are there 2 separate fuses that need to be…
Christopher Chipps
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Golf 7 key stolen, which fuse to remove to disable car key reprogramming?

My Golf 7 key was stolen. I have reprogrammed my keys to disable the stolen one. The thief could still reprogram the stolen key as he can open the door using the hidden emergency door lock. Which fuse can I remove to disable car key reprogramming…
oxygen
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