I have a 2001 chevy silverado that must have a short in it as it has killed three batteries . if i take ground wire off overnight and put it back on in the morning the truck will start. If i leave it on it will not start in the morning. I thought about using a kill switch but somebody said it might affect the computer. Any suggestions

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Question moved to model category.

There is help in the link, but you have a dead short somewhere. One trick you can try is replace the fuse, and the fuse box cover. Put blankets over the headlamps. Turn the garage lights off and let your eyes acclimatize to the dark. Then whilst looking into the engine, get someone to crank the engine. Look for a flash in the wiring.

More ideas here, starters, relays and stuff

https://www.google.com/search?q=2001+Chevy+Silverado+LS+5.3.+Every+time+I+try+to+crank+it+pops+the+Ignition+A+fuse

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How many wire's or the connector ? One connector at the fuel tank connection . 4 wire's - two for the fuel pump - gray is battery power an black is ground for the fuel pump . Two more wire's - fuel level sending unit . purple & orange with black trace . One more connector - this is for the fuel tank pressure sensor , has three wire's , this one has nothing to do with the fuel pump . This is for emission testing only

Check connection and ground. Since the brake light pin on your wiring harness has power, check that the wiring harness ground pin has zero ohms to ground. If the harness is good and the hitch light works on a battery, then there is either a bad connection from the pin to the hitch light or from hitch light to ground.

It sounds like a short you can test by removing the NEG. cable from the BAT. put a volt meter from the POS. red lead on post of BAT. and black lead to engine block or known good ground if you read voltage you have a short .
Your tow and hall switch sounds like the place to start look at the fuse box although a blown fuse would cut power off to it but look anyway.
Next check all of your lights brakes blinkers running reverse tow and hall means you have a plug to hook up to trailer lights some ware . It could also be a brake switch at the brake pedal. You need to think its likely some thing vary simple a bad connection at a bulb or lose ground wire but its in the lighting system .This could have shorted the tow switch out see if you can reach up under the dash and unplug the tow switch but check all these other things first think about the problem before you do things you can't prove

CHECK GROUND WIRE TO BATTERY

is your tow/haul button pushed? is the tow/haul light burned out? i would ask myself these questions

I'd avoid tapping into the vehicles electrical system or it can mess with computers. Take power directly from the battery. use either a three way switch, using the center as "neutral". This can be wired with "normal" gauge wire. Run a larger diameter power wire to a pair of relays, each connected to the switch. Attach the "up" power lead from the pump motor to one relay, the down to the other. Attach ground wire to the chassis.
You also have the option of using two independent push buttons instead of a three way switch...each would then serve one relay.
If you want to get fancy, you could put fuses or breakers in the power lines as well.

take the six bed bolt loose and then take three buddies slide the bed back put in the new pump slide it back n place and put the bed bolts back in. if u drop the tank u can easily break the hard plastis lines that go to the fuel tank. u only have to take the fill lines and taillight wires loose this way its alot quicker, and easier.

It sounds like there is a wire shorted out or grounding through your brake lights, I would start by looking at the wires that lead to the trailer light plug by the rear bumper.

I had similar problems, with dash board lights and headlights flickering, and the problem was a dying alternator. After I changed it, everything got back in normal. Also, a bad alternator eventually will kill your car's battery, too. I hope this will help you.