Dumb-Asprin Question on fuse panel

[RSBob]

Have a '71 with the standard under dash fuse box - but what side is the side which goes to the electricals (switches, radio, motor, etc) versus the power side. I am guessing the side closest to the firewall/gas tank supplies the switches - but testing that side with my primitive electical tester shows that the polarity is reversed - where I would think the power should be positive (coming out of fuse block) it shows negative when I connect the positive lead to ground. Being no engineer this seems like the exact opposite.

So what I want to do is connect my newly installed electric washer pump to the fuse box (through my switch) - but which fuse on which side of the block? I am assuming I need to disconnect the battery first unless this can be done carefully.

Sorry for the lame question but if I get an answer, I promise I won't ask again.

Gracias

[Jared at Pelican Parts]

Check for 12V on either side of the fuse terminal with the ignition turned both on and off. I can't remember which side is the hot lead.

If you are showing -12V on your multimeter, it means you have the test probes reversed. Should not affect anything in this instance. You have 12V. Read the manual for your multimeter about test probe configurations.

[Dave at Pelican Parts]

Pull the fuse before you check to break the circuit. If you leave the fuse in place, then both sides of it will have the same voltage.

--DD

[RSBob]

Originally Posted by Dave at Pelican Parts

Pull the fuse before you check to break the circuit. If you leave the fuse in place, then both sides of it will have the same voltage.

--DD

Dave - that is exactly what I need to do. I wish I could blame my cold on lack of synapse power. Thank you again for being such a valuable resource to all.

[Jared at Pelican Parts]

forgot to add that. sorry