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Rausche

Stock Gm Hd Dual Battery Wiring

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At some point I'll be pulling enough juice to warrant a second battery. I know that most of us use the stock GM HD Aux. battery tray, but does anybody know how GM routes the secondary battery wires?

 

I assume that they'll run in parallel, but how and where do they connect the two batteries together? At the starter?

 

Since my copy of the factory service manual seems to be junk, I'm curious if anybody can get me a diagram, so I can start thinking about what I'm doing with this project when the time comes.

 

TIA.

Edited by Rausche

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Gm routes them across the radiator shroud to the extra battery for the positive and then just ground the neg to the frame rail and you will be fine. depending on what you are using it for, i would isolate them somehow, weather it be a dual battery isolator or a big relay. ( i use a relay ) if you want to see how i did my dual battery set up, check out my pics in the feature truck contest. you can see how i did it in there.

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Does anybody know the GM P/N for that battery cable? I would want this install to be as stock as possible (even if I end up upgrading the cabling later).

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I have seen a junction box on NNBS SUV's that's on the cowl. I should have taken it out insted of cut it. I bet the NNBS would work on our trucks.

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Does anybody know the GM P/N for that battery cable? I would want this install to be as stock as possible (even if I end up upgrading the cabling later).

 

you are gonna pay thru the nose for this part. i dont know the number, but if you go to your parts dept and tell them to look under the "trailer" package trucks, they will find it. thats how you find the batter tray too. and dont forget you need the bolt and the battery bracket to hold it down

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you are gonna pay thru the nose for this part. i dont know the number, but if you go to your parts dept and tell them to look under the "trailer" package trucks, they will find it. thats how you find the batter tray too. and dont forget you need the bolt and the battery bracket to hold it down

 

I'm more or less just curious how and where it is attached to the truck. I've also been told about the Auxiliary battery relay from GM, so I have to do some digging and find out what GM's stock method of controlling the auxiliary battery is...

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ya i did this in my denali xl.. worked great.. you can get a battery bracket for a duramax truck and it bolts right up in the pass fender right by the hood hinge..and u can go to your auto parts store and pick up some cables and connectors and save alot of money then buyin the ones for gm...i think it was 150 for the cables from gm or somthing crazy like that. and just hook them up in parallel and your done..pretty easy ones u dive in

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ya i did this in my denali xl.. worked great.. you can get a battery bracket for a duramax truck and it bolts right up in the pass fender right by the hood hinge..and u can go to your auto parts store and pick up some cables and connectors and save alot of money then buyin the ones for gm...i think it was 150 for the cables from gm or somthing crazy like that. and just hook them up in parallel and your done..pretty easy ones u dive in

 

Maybe so, but I'm still looking for the GM P/Ns for the cables and routing diagrams of how they're installed.

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Will this Auxiliary Battery Schematics help you?

post-1454-1216078413_thumb.png

 

That gives me a pretty good idea of how GM does it stock...

 

I just need to go out and find the mounting locations of their relay and control boxes, and get my hands on the stock wiring for the dual battery setup...

 

Think I'm going to do this as stock as possible now...

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UPDATE:

 

I was able to obtain an exploded-view diagram from my parts guy at the dealer.

 

Once I figure out what I need I will posting all of the P/Ns and pricing for this job.

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UPDATE:

 

I was able to obtain an exploded-view diagram from my parts guy at the dealer.

 

Once I figure out what I need I will posting all of the P/Ns and pricing for this job.

I want to do this to my truck also, since the e-fans are drawing alot, with the a/c on too. Should be easy to do. good luck with it sorry i don't have any part #,s for you.

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