51 mercury push button start problem please help

I have a two wire push ****on starter on my car and it has a painless wiring harness in it the car has also been converted to 12v.
One wire goes to starter solenoid the other goes to the two position key switch.
When the dash is not attached to the car but laying on the seat turn the key push the ****on the car starts. When I put the dash Back up in its proper position and turn the key the wire smokes and burns itself up

Please help

 

Your car was originaly a positive ground. Now when you push the ****on your creating a dead short, isolate the ****on so it dosent short out or instal a more modern switch that has the starter cycle.

 

I dont even get to the point of pushing the ****on i just turn the key and the wire from the key switch to the push ****on smokes then burns up.
The push ****on start is a chrome one from advanced auto parts, picked it up about a month or two ago

 

the ****on may be bad, when the dash is not installed it has no way of grounding, once install the short in the switch has a place to go.

 

Didnt think about that any recommendations on ****ons that will fit without having to grind the hole in the dash out

 

get another of the same switch and try that first.

 

Fair enough ill give that a shot

 

Yo! I may be reading this wrong but I think you have a bigger problem.

If you are trying to use a stock ****on that completes the GROUND side, not the hot side like a traditional SBF relay does. You NEED to replace the relay and get your wiring right. You are sending a ton of amperage directly to ground, that is your problem.

 

is it the old keyed switch?

 

I agree that the solenoid needs to be changed. The 6V (pos gnd) unit is triggered by grounding, the new 12 V (neg gnd) unit is triggered by bringing the hot lead to it.

The old starter push ****on (a single terminal switch to ground) worked by grounding the solenoid trigger wire. If you want a push ****on, you need a new switch that will take a hot lead on one terminal and a wire to the new solenoid on the other terminal.