my bravo 1 drive will only go up if i use the trailer switch , checked the switch and jumped it out still nothing i do have 12 volts @the switch

You need to replace the up relay. I'm not sure of the wire colors but there are two one for up one for down.

The trim limit sender on the drive is probably bad or the wires are cracked.

Up is blue for sky down is green for grass.

I believe you can switch the up and down relays, just to rule this out before buying one, if you switch them, and the problem reverses(now the down doesnt work) then it is a relay, if not most likely the sender or wiring.

If it goes up with the trailer switch, It's not the relay, It's something in the trim limit switch, like griff said.
larry