2003silverado1500hd 5th wheel hitch

[mrhab68]

I am going to install a 5th wheel on my truck and am wondering about precautions for welding on the truck. Do I need to disconnect the battery or computer? I do not wish to fry anything. The previous owner had a 5th wheel hitch in it but removed it when he sold the truck. The brackets that go under the bed and connect to the frame were only bolted to the rails. The bolts had worked loose and wallowed the holes in the rails. I dad a 5th wheel hitch installed on my previous truck ( 94 GMC ext. cab Z-71) by a camper dealer and they tack welded and bolted the brackets to the truck rails. My truck,2003 Silverado HD 4 door with 6.0 engine is already throwing a P1516 code and I don,t want to compound this problem until I get this taken care of. I have cleaned & used silicon grease on the connectors at throttle body and the TAC module. I have been about 200 miles and no light yet. Any help would be greatly appreciated.