Couple months ago, i pulled the factory aux battery tray and harness out of a 3500 cab and chassis, tryin to hook it up in my 99 and cant remember to save my skin where the wire going over to the fuse box connects!! It comes out of the fuse box that sits in the aux battery tray and runs across the firewall to the fuse box i just cant remember if it goes to the small post that i do believe connects to the first open fuse slot or the same little bolt all the other battery cables run to.... Any help would be appreciated!!!

 

You are talking about the aux battery relay, right?

The positive from the battery goes to the starter, the negative to the engine (behind the intake), and it looks like the relay connects to the fuse panel in the cab. See the attached PDF.

 

The connector in the harness by the accumulator goes to the interior fuse block, this wire comes off the fuse holder that snaps into the aux battery tray between the battery and firewall and runs across firewall and i know i took it off of the underhood fuse block but cant remember if it came off of the post shown in the fuse box diagram as going to the 40amp fuse for if it connects where the rest of the battery cables connect to the fuse block... Which isnt shown in the diagram... And this wire is a red wire....

 

This is diagram i have been looking at that doesnt show this wire....

 

This help any?

Edit: Well damn found the same diagram haha. I guess im not following what you are saying. The harness you have has a wire on it that is not mentioned in the above diagram?

 

Maybe?

 

The fuse box on the battery tray, that in the diagram says it is supposed to be 125A, has a 40A fuse in it. There are two wires going into the fuse block on the left side and one on the right side. The tan(brown) wire goes to the connector by the accumulator on the firewall, the black to ground, it apprently pulls power from the 4wd circuit under the dash for the power for the aux battery relay control side.... Its the wire coming off of the right side of the aux battery fuse block that goes to the under hood fuse box im having issues with, wondering if it doesnt connect to the bolt the rest of the battery cables connect to or if it goes to the #1 lug that in the fuse block diagram vnnects to the #1 maxi fuse, took some pics.... If i need to i can pull the fuse box cover off...





This is fuse block on the battery tray the two wires on left go to the battery and the orange to the relay....the one on the right goes to the fuse box across the firewall




This is the relaythe top wire comes from the battery tray fuse block, lower goes to starter solenoid....




The top wire is the one fron the ride side of the fuse block i just cant figure out where the hell it connects to.....

 

Wire in question is in diagram runing across the top of the accumulator....

 

I had found a how to on this somewhere a while ago when it was just a like to do that in the back of my mind... Now that i need it i cant find the damn thing!!!

 

found this diagram, looks like it goes to the #1 post that seems to connect to the first maxi fuse