What Is This Wire?

motuGMC · January 28, 2011

I have a 2008 Yukon XL Denali and I see two wires coming from the positive terminal. One wire goes to a 175 amp fuse on the firewall which splits off to the alternator and fuse box.

The 2nd wire from the positive terminal heads towards the firewall wall and disappears. What is that wire for?

nickvrebel · January 28, 2011

I can't go look for myself right now, but I think there is a wire from the starter straight to the battery. The starter is in about that area (passenger side rear of the motor, directly below Firewall area

BigBlueLB756 · January 28, 2011

Cut it and see what don't work anymore.

JK, JK.

441G · January 28, 2011

i have that cable in stock - the other wire looks like it has a starter solenoid lug on the end

motuGMC · January 29, 2011

So its the wire straight to the starter. I want to do a dual battery setup using a battery isolator and connect all the 12v sockets, stereo, and OEM entertainment system (DVD) to the 2nd battery only. Do I just connect the fuse box to the 2nd battery?

jrrod2004 · January 29, 2011

So its the wire straight to the starter. I want to do a dual battery setup using a battery isolator and connect all the 12v sockets, stereo, and OEM entertainment system (DVD) to the 2nd battery only. Do I just connect the fuse box to the 2nd battery?

Not likely, since the isolator would prevent power from the main battery from being used, you would have to direct connect your electrical connections to the second battery for it to draw. if you use the OEM route with OEM cables and plug into the OEM power wires, you will be using the main battery. you will be running power wires to the second battery.