13

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 removed):

enter image description here

Normally I'd remove a fuse and test the two connections with a multimeter set to measure Ohms / resistance, but removing this is a non-trivial task - not only is the bolt holding it in place incredibly stiff, it's also holding the wiring together and I don't like the risk of re-assembling the wiring incorrectly or losing one of the many small parts like washers held with this bolt.

In theory, it looks like I could (after disconnecting the battery!) just use the multimeter's prongs to touch the copper visible on the left and right sides of the bottom of the fuse, and if it gives any reading, in theory that would mean the fuse hasn't blown. Some instinct however tells me that poking inside this fuse like this is a bad idea, or that it might not be as simple as it looks and those might not be points that are connected only by the fuse.

Am I worrying too much? Can I test this fuse without removing it as described?

user56reinstatemonica8
  • 2,648
  • 12
  • 31
  • 58

3 Answers3

17

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 the fuse. If good it will read battery voltage on both sides. Most fuses have exposed metal tabs on both sides of the actual fuse section for this purpose.

On the fuses shown check for voltage at the small legs near the side of the case in the lower section of the picture.

Fred Wilson
  • 11,667
  • 3
  • 30
  • 49
7

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 terminal and the other side of the fuse. Should be zero or close to it. If so, it is good. With this type of fuse, when it blows, there is usually a large gap due to the amperage it takes to "blow" it.

X-tech2
  • 939
  • 4
  • 9
0

To remove the fuses take the 3 bolts on the side out that hold the black cables to the fuse box, the loosen with a thin flathead on the front part of the fuse and lift. They come right out.

veroweg
  • 1