Fuse not stock
 

I have 2 fuses in the inside panel that have wire coming out of them I assume this is not stock
Truck was a Fire Rescue vehicle before I got it.

https://cimg6.ibsrv.net/gimg/www.f15...dba0446ea4.jpg

Those are add-a-circuit fuses. Often times used to run lights, etc. Not the greatest idea on the planet, but they work.

The side with a wire goes on the hot side, then you are supposed to have that wire fused, creating another circuit.

Are you sure about the side with the wire going to the hot side white89gt?
I would think that the non wire side of the fuse goes to the hot side of the fuse block, then going through the fuse link and protecting the wire coming off the top of the fuse.
But, I could be wrong.

I guess it depends on what you want. A unprotected new circuit, or a protected load side feed.

You can replace that one with a piggyback fuse block. They incorporate another fuse dedicated to the add on component. Only problem with those is, they are bulky and the cover won't fit over them in the OEM fuse block. It's better to tap elsewhere with an inline fuse holder.

Yes I am sure. That is why is is called add a circuit.... not add to a circuit. Like I said, you fuse the wire. Newer versions of these actually stack a mini fuse on top of the fuse, forcing it to be fused.

Understood

That wire should have an inline fuse. Or it did when it was hooked up any way. Jbrew is right that type is used when there isn't enough room for the piggy back type. Now ford ships explorers pre wired for law enforcement use.

The Crown Vics came "pre-equipped" as well. The state of Utah deemed the wiring as not being heavy duty enough, so they added their own circuitry anyway. My friend used to install all of that stuff in the UHP vehicles.

By son Builds police cars along with most any other vehicle that's needs lights and what have you.

The company he works installs a system in K9 units that if the dog is in the car and the temp reaches 78 it drops the windows 1 inch and turns on fans. If it gets to 80 turns siren and lights and sends a radio message to the officer and dispatch.