troubleshooting a short

[oldryder]

so.... you got an electrical problem and immediately blow a fuse after turning on the ignition.

try this. wire a tail light or other 12 volt lamp in series between either battery cable and the battery. The light will act as a current limiter and allow you to have power for tracing the short without blowing a fuse right away.

[tkent02]

Good idea.

[Steve]

Thanks, I had not thought of that before.

If you are doing this so that you can use a test light to follow the wires, be sure to use a light in the fuse holder that is brighter than your test light.
If it is about the same or dimmer than your test light, it will limit current so much that your test light won't work.


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[n1elkyfan]

I had never thought of that but definitely a good idea I will have to remember that for next time.

[trippivot]

yep that is a very good tip for scouting a fuse blowing short.
(positive power shorting directly to ground without a load or control switch)

this is the key for that tool tip


Bright light = short circuit
no light = no power and problem still exists
Dim light = proper circiut