46
votes
Accepted
Why don't cars have circuit breakers instead of fuses?
(1) Fuses are cheap. Really cheap. You can get a variety pack of 100 for $8 or so. Circuit breakers for 12V systems are available, but are not cheap (more like $10 each). My car has 40 or 50 circuits, ...
- 576
22
votes
Accepted
Should I replace fuses as a part of regular maintenance?
Fuses do not need to be replaced unless they have blown, so it's not a regular maintenance thing.
In terms of checking them, depending on your vehicle, many only require a visual check to see if the ...
- 18.6k
22
votes
Accepted
40amp protection on 25amp rated wiring?
The maximum rating of 25A will be for continuous use. The 40A fuse is there to blow very quickly in a fault condition.
If you look at this page https://en.wikipedia.org/wiki/American_wire_gauge 2mm² ...
- 24.8k
17
votes
Accepted
How to test a bolted-in heavy duty 50a / 80a / 100a fuse with a multimeter without removing it?
Instead of Ohms checks of fuses I check for voltage with power on. Set your voltmeter to DC volts with the negative lead on the battery negative connector. With the positive lead test both sides of ...
- 11.6k
14
votes
How can a fuse drain a car battery?
It wouldn't be the fuse which is causing the power drain, but the circuit the fuse is there to protect. (This is the reason why the copied area you have posted has 5 "Not Helpful" votes against it.) ...
- 153k
14
votes
Why don't cars have circuit breakers instead of fuses?
I don't have a definitive answer, but believe it is a combination of factors and boils down to the following:
Cost: While both do the job of protecting circuits, a fuse runs you cents per unit, while ...
- 153k
12
votes
Accepted
Fuse box above battery melting
As I understand it, there was a fundamental redesign in the cars from around 2002 onwards. Unfortunately that doesn't help you but I wonder if it is possible to retrofit the later model fuse box.
...
- 23.5k
11
votes
Should I replace fuses as a part of regular maintenance?
As a general maintenance practice or a troubleshooting method without having a particular reasoned approach, no. If it's troubleshooting, testing the fuses on their exposed blade tips is equivalent.
...
- 141
10
votes
Accepted
Fault find blown cigarette lighter fuse
You have a short somewhere.
The purpose of a fuse is to be the weak link in a circuit. If more current is running through a circuit than it was built to handle, a fuse will self destruct and break ...
- 3,012
9
votes
Accepted
How to remove the 50 amp, 80 amp and 100 amp fuses from the positive terminal of a RAV4?
The fuse connection legs are through bolted on many of these higher amp rated fuses. To find out remove the black plastic cover below the fuses. If you find small nuts then they are the bolted in type....
- 11.6k
9
votes
Could corroded or incorrectly soldered battery teminals cause parasitic drain?
Have a look at this picture:
From here.
Corrosion (the green stuff) can conduct electricity.
If one wire in that picture went to the battery positive terminal and the other went to the battery ...
- 201
9
votes
I have a distribution block buried under my center console. Would getting 12v from that line vs directly from the battery present any fire hazard?
The fuses are there to protect the wiring, the fuse needs to blow before the wiring gets hot. You say that you have a fuse at the battery end of the 4 gauge wire, so that wire is protected against ...
- 24.8k
8
votes
Accepted
Indicators Not Working But Hazard Lights Working
Traced this problem to a fuse under the dashboard, located in the middle horizontal row right most fuse. Turns out this fuse is the indicator fuse and when this fuse is blown the indicators won't work ...
- 373
8
votes
Why don't cars have circuit breakers instead of fuses?
In addition to the other good answers:
You'll see self-resetting circuit breakers in heavy-truck applications, which is a far more abusive environment, and prone to intermittent faults (esp. in ...
- 311
7
votes
How to test a bolted-in heavy duty 50a / 80a / 100a fuse with a multimeter without removing it?
If you can get to both sides of the fuse, see if you have power on each side. If you want to make sure, remove the battery terminal, and use an ohmmeter to measure the resistance between the battery ...
- 779
7
votes
Fuse box above battery melting
I had to deal with this problem some years ago on a VW. What I noticed is that the fusible link ran slack, causing the connection to arc and as a result burnt out the plastic housing below. I couldn't ...
- 166
7
votes
Should I replace fuses as a part of regular maintenance?
Replace them all? No. As others have mentioned, they're either working or they're not. Test them with a multimeter or fuse tester. Be sure to look for "fusible links" in the wiring on a newer car, ...
- 171
7
votes
Accepted
Golf 7 key stolen, which fuse to remove to disable car key reprogramming?
There is no fuse to remove that will disable immobilizer programming. You can how ever remove the fuse for the obd2 power. That will slow someone down since their tool would no longer be powered and ...
- 3,790
6
votes
Fuse box above battery melting
Replace the wire between the alternator and the fuse box.
It's called the alternator harness, but I haven't found it for sale online. It is just a simple (large) wire with two ring connectors ...
- 1,945
6
votes
Accepted
Radio and Charging Outlet Stopped Working
They are typically on the same fuse. Charging outlet should be listed as a cigarette lighter.
- 8,443
6
votes
Accepted
How to diagnose blown tail lamp fuse
The parking lamp/headlight switch applies power or ground so the circuit would be open if you were testing with the switch off.
Same with the turn signals.
The tail lights are on separate circuits. ...
- 10.7k
6
votes
Seat heater fuse at 12V even when ignition is off?
There are three fuses for the seat heater system
1) Passenger fuse box: Fuse 20, 7.5 amp. Supplies Seat heater control unit.
2) Passenger fuse box: Fuse 5, 15 amp. Supplies relay power pin.
3) ...
- 11.6k
6
votes
Accepted
Does a constant blown fuse always indicate a short?
If the fuse is blowing as soon as you perform an action it's a short to ground.
Multimeter won't do much good in this situation. It'll come down to wiring diagrams and visual inspection of the ...
- 10.7k
5
votes
Fuse box location for 2006 Renault Scenic
I found manual here.
The fuse box information is on pages 5.18 and 5.19, if you download the PDF:
So it looks like it depends on whether your Scenic is a UK? model (steering wheel on the right) or a ...
- 1,146
5
votes
How can a fuse drain a car battery?
You mention, "no draining electrics," can you say more about how you determined this? It's important because "a self-draining battery" requires something that is causing a load on the battery – ...
- 14.4k
5
votes
Accepted
Blew the fuse for the battery
That would work, but it's a very dangerous solution. The fuse exists in the circuit as a safety mechanism. If the circuit is flowing more power than it can safely handle, the fuse self destructs and ...
- 3,012
5
votes
40amp protection on 25amp rated wiring?
I would suggest that you should find the source of the fault - probably in the wiring as you suggest as it could get worse and cause a fire (not the best thing in dense traffic with no place to go).
...
- 34.6k
5
votes
Accepted
Could corroded or incorrectly soldered battery teminals cause parasitic drain?
The effect of corroded or poorly soldered battery terminals is responsible for excessive voltage drop, not parasitic current drain.
They are not the root cause of the parasitic drain.
- 39.1k
5
votes
Accepted
Given a fuse panel, which way should a fuse tap be facing?
If you are running an inline fuse (which you should), you put it on the power side. This is so you don't overtax the fuse you're tapping off of. To tell which is hot, pull the fuse and check each side ...
- 153k
4
votes
Accepted
BMW E90 pre facelift - REST heat button / fuse
From what I understand and how I've seen it used.
If the ignition is off it uses the residual heat from the engine to warm the car.
In order to validate my claim, turn your car off and hit the ...
- 33k
Only top scored, non community-wiki answers of a minimum length are eligible