If you close the direction contacts, short batt neg to m- and nothing happens, then it's a fuse, cable, contact, motor or battery.

You said lift was ok, so we can rule out battery.

When you say 'no voltage' at the contacts, how are you measuring it?

There should be a batt-pos there...
Basically, one side of the armature gets a pos, it goes out teh other side to the normally open side of the contacts (should be the bar that conects the top 2 posts)
When the contact closes, it puts that batt. positive onto one sid of the field, then back out to the other field contac, which will be normally closed to the m- post on the pmc.
The pmc chops that to batt neg to control current.
The A2 post of the pmc conects to the top bar of the contacts, to allow plugging current to pass throught the plugging diodes inside the pmc.

If all the wires are hooked up and powered properly and the unit jumps when shorting the m- to batt neg (with direction contacts closed) then it's likley a pmc.
If it doesn't jump, then it's in the cables, contacts or motor 100% for sure.

If it's pulling in both directions at the same time, you open up the motor circuit at the fields.
If the contacts are cabled incorrectly, then you'll have anthing from no travel, to 1 direction only, to both directions go the same way...

So long as the battery has ok voltage, don't worry about the charger thing.
If the battery is too weak, the contacts will chatter as load picks up, since lift is ok, this can't be the problem

Just follow that batter positive from the armature all the way to the pmc.
You might have a problem in the motor circuit that onl shows up under load, so look for a voltage drop while having the batt neg shorted to m- (with a direction contact closed of course)
Generally, contactor problems will manifest themselves with a problem in 1 direction oly, so you're probably ok there.
Armature and cable problems will be in both directions...