wats up ppl so i think i messed up somewhere and i need help
so i put in a tac from harbor freight into the truck and wired everything to the fuse box and now the truck wont start i removed all the wires and it cranked over just fine re installed them and now it wont turn over at all...can any 1 help

 

Most tachs are 4 wire setup:

1. Negative/ground
2. 12V power source - usually to a wire from the ignition harness that is "hot" when the key is in the run position.
3. Ilumination - to a wire on the head light harness off of the head light switch that is hot when the lights are on
4. Coil (to the negative side of the coil) or to the tach terminal of an aftermarket electronic ignition module.

You shouldn't be wiring it to the fuse box at all. What tach did you get from HB? The 2" LED tach?

 

ya its the little 2 in 1

 

This is the only tach I saw on their page - http://www.harborfreight.com/2-inch-...ter-98480.html

If this is the case then:

1. Black wire - Attach this wire to a good ground. make sure that the wire is touching bare metal (dash frame is usually good). Make sure to test it with a test light to make sure that you have ground.
2. Red wire - Turn the ignition key to the run position (do not start the truck) and with a test light see what wire has power to it. Turn the ignition to the off position and then test that wire again and see if it still has power. If it does not, that is the wire that you want to attach the red wire to. If the wire still has power, then repeat this step till you find a wire that has power with the key in the run position and no power with the key in the off position. I find it odd that they recommend you install a 1 amp fuse on the red wire but I would if they say it's recommend.
3. White wire - You will perform basically the same test with the headlight switch as you did with the ignition switch. Turn the the headlight swich one so that only the parking lights are on. Using a test light, see which wire has power going through it. Turn the head light switch on so that the headlights are on and see if the wire still has power (it should). Turn the headlight switch off and see if that wire still has power. If it does then repeat test till you find a wire that has power when the parking lights and head lights are on but doesn't have power then they are all off.
4. Green wire - You want to attach this wire to the negative terminal on the coil pack. If there is a stud and nut terminal on the coil, then attach an eyelet connector to the green wire, remove the nut from the negative terminal and attach the green wire.
5. Orange Wire - You will wan to find a wire under the dash that has constant power no matter what position the key is in. This is the wire that you will attach the orange wire to. I would start looking at on of the wires on the ignition switch harness as there is at least one that is always live. If you can't find one, then run it off the battery and wire a 5 amp inline fuse so that you don't drain your battery.

Make sure that you disconnect the negative battery cable first. This will help prevent any damage that could happen due to cutting the wrong wire. Also, any wires that need to be run through the firewall should go through a rubber gromet. And try to avoid the exhuast as a melted wire can reck havok on an electrical system.