Sassy Salvaged Silverado Troubles

Hello I salvaged a 2003 chevy silverado from a dealer. It was/is in excellent shape and only need aesthetic body work things done to it to repair it from a auto accident. Before buying it, the dealer guy hooked up a battery to it and put on a MAF sensor and the truck ran smoothly with all systems goo. So I bought the vehichle and towed it home (no plates). It has 103800 miles on it. The engine size is a 4.8 liter. I bought all aftermarket body parts for it, such as the hood, grill, etc. The ONLY mechanical things I need to do to it was hook up the mass air flow sensor, install a new driver side air bag and buy a new radiator. Before I connected the MAF sensor, I would turn the truck on and it would idle or run perfectly. If I put it in gear, it would cut out. The Dealer said it was because it needed a MAF to keep it going. So a friend of mine gave me a mass air flow sensor from a 2002 chevy tahoe with a engine size of 5.3 liter. I installed everything except the air bag, put all the front body pieced on the car and the MAF and new radiator. I went to start the truck and it starts perfect, but when I put it in gear, the truck loses power and cuts off. I would turn it on and try to switch the gear to neutral right quick, but it would turn off, even if I tried to rev it simultaneously. Some of my electrcial went hay wire immediately. When I step on the brakes, the two turn signals lights come on. If I have the truck Idling in park, it will cut off if I turn on the head lights switch. I could not even move the vehicle out of Park without is shutting down. Months later, last week, I let it idle a while and went to move it to get my boat out. It moved perfectly when I put it in drive and reverse. I was like wow. I drove it around the block a while. But it immediately loss power when I turned on the head lights switch also all my gauges went to zero. If I switch the lights back off, the truck powers back up. Also when I step on the brakes or push the horn (where the air bag should be) the turn signal lights come on. I do not now where all this is coming from. At the dealership, the truck drove around perfectly, but he didnt turn on the headlights because it was during the day. Is it because of the improper MAF sensor I installed. I thought it may be the Body control module so I uninstalled it from the dash board to replace it, but I haven’t replaced it yet because I wanted to get a second opinion before thinking my project is a bust. I purchased this truck for $2,800 after finagling the dealer down from $3,900. I assumed I would have to only put maybe $1,000 into it, but if I have major trouble, I fear my cost saving investment may be going belly up.

There is an ELECTICAL PROBLEM, not electronic (ecm, maf,etc). A knowledgeable person, with an electrical multimeter and the wiring diagram, shouldn’t have much difficulty with this problem.

The first thing I would check is all the wiring in the steering column. If the airbag went off it is highly possible the explosion damaged the ignition switch, turn signal, headlight dimmer, windshield wiper wiring. It would not be uncommon.
~Michael (dartman69)