Best Answer


I have seen several fuse that appear ok, and in fact are defective.

The best way to test, is with a computer safe test light, there not cheap but if you want to get serious about auto electric you need one.

To test fuses, you are generally safe with the cheap kind.

1) Plug in or clip on your test light. 2) Test your test light against a known good source for voltage. 3) Turn on the ignition switch. 4) Probe both sides of your fuse, the results should be the same. Note that one or two may be cold on both sides (or negative if you have a computer safe tester) They generally power the interior lights. 5) If you find a fuse that is cold on one side and hot on the other, you have found the monster. 6) Replace it with the same type and size.

IF all tests well and you have glass fuses, test the metal clip on both sides that it clips into. They may require cleaning, and careful bending from water/ rust damage. If you have plug in fuses, check the integrity of the fuse holder.

I have seen all types and sizes of fuse, especially glass, that appear good, but are blown.


Best way to check a fuse is take it out of the circuit and test its resistance. A good fuse will have very low resistance (less then 1 ohm). A bad fuse will measure "Overload" on your meter. You can get a cheap meter from and local hardware store for ten bucks. Even bring the fuse with you. The guy at the store will probably check it for free for you. Good luck.

User Avatar

Wiki User

โˆ™ 2015-07-15 21:18:36
This answer is:
User Avatar
Study guides

Add your answer:

Earn +20 pts
Q: Can a fuse appear to be good but in actual fact be blown?
Write your answer...
Still have questions?
magnify glass
Related questions

How to replace a blown brake light fuse?

Remove the blown fuse. Replace it with a new fuse.

What do you do when you've blown a fuse?

A fuse is a deliberate weak link which will be blown if there is a power overload. When you blow a fuse, take the blown fuse out and throw it away as you would a blown light bulb, and replace it with another fuse of the same type. * In the old-timey fuse boxes a penny could be substituted for a fuse, but a penny is too strong to be blown, and the next overload will burn the house down.

When the wire or foil strip inside a fuse melts what is it called?

It is called a blown fuse.

Why 2002 Dodge Ram taillights not working?

Either blown bulbs or blown fuse check for blown fuse first under hood in fuse box labled taillights

What is easily blown?


Can blown fuses cause the motor to run hot?

simply having a blown fuse would not cause the engine to run hot. But, it depends on what fuse is blown. a fuse blown for the cooling fans would make it run hot.

How do you know when you've blown a fuse in a 1989 Chevy Celebrity station wagon?

You know your car has blown a fuse if whatever the fuse is for suddenly quits working. For example if your radio is playing and for no reason quits it may be a fuse has blown.

How do you tell if a healamp relay is blown?

You can tell if your heal lamp relay is blown is by inspecting the fuses. If you look closely at the fuse, you will be able to tell it is blown or not. If you see a separation in the fuse, it is blown.

I have a Mercedes s430 and the door locks and the trunk will not open could this be a blown fuse?

There is a fuse blown I think is f31

What could be the problem when the dashboard lights and taillights are not illuminated?

Im 99% sure you have a fuse blown, its the parking lamps fuse. a fuse may be blown

What is the technical term for blown fuse?

The fuse is said to have 'operated'.

How do you tell if the engine fuse is blown on a 97 Mitsubishi mirage?

Pull the fuse out and have a look at it and if the wire inside is broken then its blown

People also asked