Hey all, anyone have an idea what this plug is for? I'm installing a 2nd battery to use strictly for my camper so i will be using an isolator(solinoid) and ...

Hey all, anyone have an idea what this plug is for? I'm installing a 2nd battery to use strictly for my camper so i will be using an isolator(solinoid) and need an "ignition hot" to activate. I've tested both wires (brown & black) in the plug and brown is ign. hot and the other seems to be just ground.
Since it's so close to the battery it would be nice just to tie into this but not sure if its related to AC circuit. It does come out of the same harness as low pressure switch although different colors.
I've installed these on older trucks but this is my first newer rig and herd horror stories about tapping into wrong wires.
My rig is an 2003 2500HD 6.0 w/camper, tow pkg. but didnt come with duel batteries. thx for any help.

Just a wild guess here, but that wouldn't happen to be your cabin fan would it? Seems like the right place.

hmm that braket isnt for an air injection pump is it? if so then i would bet my money on that wire being connected to the air injection pump. was the truck purhaps built for california then shipped to washington where they removed the pump.

If you want to see which circuit it is, I would hook up a meter or test light and then pull the fuse for the AC first. When the light goes out, you know which circuit it is on. My truck has the exact same pigtail hanging down and by the size of the wire, I bet it is protected by a 10 amp fuse. The easy answer to your question is yes, I am sure you can plug into this circuit and get power. You also have to look at the negative aspect of this too. If what you add, exceeds the current draw of the fuse.............then the fuse will blow...AND whatever else is on that circuit will stop working (AC, blower etc). Next. If you add a solenoid or relay at this point, you have to be sure that the component has a clamping diode so that when that new component shuts off, it doesnt send an "inductive kick" of voltage up the line and cause problems with electronics that are on the other end of that brown wire. I hope this helps. And NO..............don't put in a bigger fuse!!!!

Thx. for the help and info guys. Think I'll do as you suggest & pull fuses to see what circuit its on, but probably play it safe and and just run to the fuse box.

t-burg wrote:Hey all, anyone have an idea what this plug is for? I'm installing a 2nd battery to use strictly for my camper so i will be using an isolator(solinoid) and need an "ignition hot" to activate. I've tested both wires (brown & black) in the plug and brown is ign. hot and the other seems to be just ground.
Since it's so close to the battery it would be nice just to tie into this but not sure if its related to AC circuit. It does come out of the same harness as low pressure switch although different colors.
I've installed these on older trucks but this is my first newer rig and herd horror stories about tapping into wrong wires.
My rig is an 2003 2500HD 6.0 w/camper, tow pkg. but didnt come with duel batteries. thx for any help.

wire 1.JPG

I have the same truck as you and mine has a second battery which is supposed to be for the snow plow I believe, If it stops raining I will go and take a look see how its connected, I would also like to know how you are going to hook it up to supply your trailer, as I have a Jayco 24 FBS and I also thought that would be great to power up the trailer. Sorry for jumping in on your post.

t-burg wrote:Hey all, anyone have an idea what this plug is for? I'm installing a 2nd battery to use strictly for my camper so i will be using an isolator(solinoid) and need an "ignition hot" to activate. I've tested both wires (brown & black) in the plug and brown is ign. hot and the other seems to be just ground.
Since it's so close to the battery it would be nice just to tie into this but not sure if its related to AC circuit. It does come out of the same harness as low pressure switch although different colors.
I've installed these on older trucks but this is my first newer rig and herd horror stories about tapping into wrong wires.
My rig is an 2003 2500HD 6.0 w/camper, tow pkg. but didnt come with duel batteries. thx for any help.

The attachment wire 1.JPG is no longer available

Hey its stopped raining here so here are the pictures of my hookup for the snow plow option, I am not sure if it will help you.

Here is the other picture