starter foot switch help.

[lmdangerous]

I have converted my 51 -3800 long bed to a 250/2004r combo .I found a factory automatic column, shifter, etc and swapped it all in so as to look factory - i must say it looks good even if i did it.
NOW the problem . I wanted to keep the foot starter switch ( iknow -iknow), so I used a heavy duty foot /push button switch from a M farmall- ( 25$ ouch) and bolted it where the factory foot starter mechanism comes through the floor board.Machined the steel head for the factory switch to set on top of the new switch and it looks factory. I wired the switch using current from the battery pole on the starter sol. to the switch and the other side of the switch to the S terminal on the sol. . I soildered cannections ,shrik wrap , etc cause I am a neat freak. when i used the button it burned the battery side wire almost to a crisp, but no harm to the S terminal wire.
I checked the switch on and off the truck.Its good . I also used a screw driver to check the starter and soilinoid and it engauges and spinns over.
Whats going on ? I have checked every connection , no grounding or shorts , switch is good. Its done this 2 times in a row!
Could it be the soilinoid on the starter???
I really thought this would be easier , and lees crap under the dash - guess thats what I get for thinking
LOL
LMD