[84LX89GT]

(These are in order of easyness

One test you may try is to take a piece of wire and jumper across the park brake switch (the only switch attached to the parking brake, should be easy to identify, but you'd have to remove your center console). It is a ground side switch and if you jumper accross the wires and the top works then it's likely a bad switch.......A much easier version of this test is to pull on the parking brake and see if the red brake light lights up in your dash.

Have you tried tapping on the motor with a blunt piece of metal like a hammer (don't beat it, just tap it). If you're hearing a click it means a relay is at least activating, although it may still be bad. The brushes in the motor may have gotten stuck/gotten corroded and can be jarred loose, or they may just be worn out in which case you'll end up following a few more steps..

Find both fuses and check them (you already found one was good). It is most likely the 30A fuse is dead or your motor is dead.

There are two relays, a lowering relay and a raising relay, that get main power from a 30 amp fuse, and get control side relay power (through the switch) from a 15 amp fuse. Most likely the 15 amp fuse is in the instrument panel, and the 30 amp is in the engine compartment. One test is to check on the other side of the switch while toggling it to see if the other sides get power. One wire should be constant, and the other two should be switched, the switch feeds the control side of the relays that make them activate (click).

Since there are two different relays and the motor doesn't work up or down it is less likely that both relays failed at the same time, it may be the case, but i'd look at other things first.

Have someone toggle the convertible top switch while checking for power at the convertible motor. There should be two wires sticking off of it. One will be energized with the switch activated and the other is grounded, they are both normally grounded through the relays, the switch energizes the selected relay and the 30A power source goes to the motor, then back through the other relay to ground. Have an assistant toggle the switch, once you get power on one side of the motor go to the other side and make sure that it gets power when the switch is in the opposite position from when you got power on the other side of the motor. I have enclosed a sample diagram of a mustang convertible top diagram (this is for a '94 mustang so it's probably got different wire colors).

Keep us posted, try these, then we can go onto more complicated tests like testing relays, the grounds, etc.

Good luck, hope this helps