Graham R wrote:
From what you describe, the motor/ pump is clearly working. First of all try checking if the plug in relays at the pump/ reservoir are not loose; then swap them over. Then, check the wires from the trim switch at the pump/ reservoir. I can't remember the colours, but down is +ve on one wire, up is positive on the other with a common ground! If the problem is not there, it's further "upstream" towards the trim switch.
Graham
+ 1 for this.
Could be a switch, or the disconnects on the engine package that lead to your trim motor. Try a little dielectric grease to get a better connection. If the motor was running trying to go up as well, then you should check the fluid level.