Hey Edward,

How are things going. Found the OTM cable good. Lift had been worked on by someone else and back tracking to put back in one piece. Found a positive wire going to the light switch that should have been to the fuses. We now have power to the system but have a code of 2,7. States the EPO switch is not closed. We have checked the switch and everything is as it should be. There is a relay at the steer traction manager that is solder to the card and suspect this is bad. Do you know if this can be replaced without replacing the card or does the card need replacing. Thanks.

does the voltage drop happen all the way back to the battery or only just after the key switch?
stays 24+volts on the line from the fuse to the switch? (bad key switch if only after the key switch)?
trace that voltage drop backwards to find where the voltage loss is.
I predict you find a bad fuseholder or fuse, although the over the crosshead/in the mast control wire cable is a very likely suspect too.

Can't help you with your issue, but this Komatsu unit is the same as a Clark OP15 & Prime-Mover model OE35. Unit was made by Prime-Mover in Muscatine, Iowa, the plant now produces equipment for the Toyota group after Toyota bought BT (which was after BT bought Raymond which was after BT bought Prime-Mover (sounds like a story from a mountain top in Tennessee).