thanks for the help, I did find a cable in the mast that was causing the short. It had been previously repaired with butt connectors. The butt connector was continually smashed against the frame when the forks were retracted, causing the coating to wear out on the connector and causing the short.

Look for shorts in the mast cable. Look for shorts in the cable that runs from the carriage through the pantograph to the solenoid valves out on the fork carriage. Look for shorts from any part of the electrical system to the frame of the truck.