I have a 2000 Dodge Ram 3500 5.9 cummins auto the driver side fender was junk so the guy I bought it off had ordered a bunch of new parts which it came with a new fender I pulled the old fender off and put the new one after I got everything back together I started it it was running fine I hit the brakes it shuts off and if I turn the head lights on it shuts off was wondering if it could be a ground issue or something any feed back will help thanks in advanced 

There is a ground strap at the front on the driver side fender near the headlight. There is a few ground wires near the ABS pump. 

I found the spot for the ground where does that ground go to the battery? Or frame?  

Typically frame. 

 

Just another note here... Nothing should be tied to the battery terminals the only one exception is grid heater power supply. Nothing else should be tied to the batteries directly. No lift pump, no nothing. Those should all go into the PDC on the BATT terminal. No grounds are bolted to battery terminals either unless on exception is the W-T ground wire mod if you build the extra ground lead from the drive side battery to the bolt on the gear case (optional).