Wiring in a Solenoid w/Fuse Tap for 12V Power w/Switch on Tow Vehicle to Power Camper Accessories

Question:

I want to be able to use the battery isolator solenoid with the two parts that Ive purchased from etrailer.com. I went straight with the hot lead 12v connection on my 7 way adapter part # 37185 to the battery terminal via the 30 amp Pollak circuit breaker, part # 38630, thus bypassing the wiring harness that includes a circuit fuse. Now, when I remove the ignition key, I still have power to the 7-way adapter, and this method discharges my camper battery when connected. I want to use the mentioned parts by tapping directly into the fuse box instead of running the wire to an accessory like the radio, and such. Can I tap into any amperage fuse or do I have to stick with the 30 amp throughout this whole setup? The reason is, my truck only has the typical fuses but only up to 20 amps, anything over 30 amps, the fuses are a box-type special fuse see photo attached that a typical add-a-circuit fuse tapper doest accommodate. Can I at least tap into a 20 amp fuse with my application, or do I have to get a special fuse tapper that can accommodate this type box fuse? If the latter, do you sell such an animal? Also, if you can please briefly explain on how I should route all these parts starting at the battery. Theres a diagram attached for the solenoid.

asked by: Norm

Expert Reply:

I spoke to my contact and he informed me that the solenoid will need to be tapped into at least a 10 amp fuse to be able to power the solenoid's switch mechanism.

He also told me that the amp draw will not be limited by the amp rating of the fuse that the ignition wire is tapped into.

I recommend the Firestone fuse tap # F2526 for your solenoid installation.

You will want to start at the battery and wire in the circuit breaker # 38630 then connect this to the 12v solenoid like # PK5230701 (the larger copper colored post), the out post of the 12v will run to the # 37185 12v wire (the black or purple will depend on how you have the connector on your trailer wired to your battery). The fuse tap will connect from the fuse to the solenoid switch post and the last post will be for the grounding wire to the metal frame of the vehicle.

I have linked the above mentioned parts to this page for your convenience.