Voltage to run/accessory fuses without the key on?

[chuckludwig]

Perhaps I am fundamentally misunderstanding something, so perhaps someone can chime in:

I'm trying to wire something into my fuse box (using a fuse tap) that should only be on when the key is switched accessory or run. It was my understanding that the F5 or F6 fuse would do the trick BUT when I test voltage to either of these terminals, I am getting 9-10 volts. The F1 and F2 are getting the full 12v.

My fear is somewhere in the rats nest of wiring the previous owner did, they somehow have something giving constant power (or a wire is worn out somewhere), but before I go hunting for a short, I wanted to check in with you smart folks and see if perhaps I'm simply thinking about this wrong and seeing 9v or whatever with the key off is normal.

Thanks in advance!

 

[Hemikiller]

Fuses 1 & 2 are always hot. Fuse 5 & 6 are switched and should not have voltage without the key in Acc or ON/Run. They also share the same buss, so power to one means power to the other. Since #6 is the radio fuse, that's a likely candidate to be butchered. However, start with pulling both fuses and probing the inner terminals that are attached to the buss. You should not have power there with the key off. If you do, then you have power coming in through 297A, which comes from the ignition switch.