OK, here's what I checked with the 9v battery. grd to#1=9v, grd to #2= 9v, grd to #3=9v.
#2 to grd with red jumper wire disconnected = 9v and needle moves
#3 the same as #2,
#4 to grd= continuity.
Another thing I noticed with the magic black box out of the circuit the two pins on the back of the gauge, grd #3 and the needle moves.
I installed the unit, with the black box installed, key on gauge moves about 1/2 of the way to the middle, start the truck and it jumps to about 2/3rd's to 3/4's of the way across the gauge, reads 14.6v on my volt meter.
I'm going to call it good and I want to thank everybody for their help.
Now I'll clean up the wiring and move on to bigger and better stuff.
