Fuse Testing

[TxGreaseMonkey]

The easiest and safest way to test under-hood and under-dash fuses is with a digital multi-meter. Set the meter on audible ohms, touch the leads to the two small metal test points (on top of each fuse), and listen for the beep. You can test all fuses in your car in 1% of the time it takes otherwise. With a DMM, you don't run the risk of removing a fuse and replacing it in the wrong slot. Additionally, DMMs are absolutely necessary for checking out relays, particularly main relays which can leave you stranded, sensors, and wiring harnesses and connectors.

 

[punisher]

Thats all well and good until you OHM a fuse and it is bad, and you still have current running through it. Say goodbye to a $6 ceramic fuse in your Fluke.

I usually ck for voltage on each side of the fuse.

Different strokes for different folks.

 

[TxGreaseMonkey]

Excellent point. Tests lights also work quite well for checking fuses.

 

[punisher]

I always lost mine. I swear I went through 10 testlights a year. Don't get me started on Snap-On black handled screwdrivers. I lost those by the dozen. I was so happy when screwdrivers got nice flourescent green and yellow handles.

 

[rpn453]

If there's a problem with an electrical component, why not just pull the appropriate fuse and look at it?

 

[TxGreaseMonkey]

That is always an option, rpn453. However, on some under-dash fuse boxes, located in dark and obscure locations, access and visibility is poor. If you want to check, say, all 15 fuses, you run the risk of replacing a fuse in the wrong socket. Many sockets don't contain fuses and are left blank. If you don't turn on your ignition, as punisher rightly points out, you can safely test all fuses, using an audible ohm meter, in 1 minute. Alternatively, turn the ignition on, set your DMM for DC voltage, and check for voltage on both sides of each fuse.

[ June 06, 2006, 11:35 AM: Message edited by: TxGreaseMonkey ]

 

[brianl703]

What about those fuses that are always hot whether or not the ignition is on?

I wouldn't stick a DMM in ohms mode on any connection in any car that isn't disconnected from the battery.