we got the front brakes converted to disc on my son’s 69.
now the brake lights are not working. i put the old switch back on.
i now see the parts store list different switches for manual and power
brakes even though the pictures look the same. is there actually a difference
in them ?
Yes, the spring in the two switches is different as it takes less pedal effort to achieve braking when the brakes are power assisted.
Thanks 1969XR7Vert
I’ll tell the parts store to get me one in.
Just an update. my brother was able to scrounge up a 69 power switch from his parts and I could see the differencein the springs. got it changed out and we have brake lights ! so after I swapped the front calipers from one side to the other we were finally able to get them to bleed. I would never have imagined it was possible to put them on wrong. 
now we have a leak at either the pv or the distribution block 
I keep telling my son, one step forward, two steps back but were gonna get there. By the way this site ROCKS. Thanks for the help.
Jeff.