My 125b will only track in low speed I was told there is a solenoid that needs to be changed is it hard to get to and where is it located
Check your fuses first. Could also be bad pressure switches. They are on the lines below your foot pedals. Try jumping them.
Two speed There is a s/n break for the machines up to the 74404 and after 74404. If the swing brake and heavy lift work that just about rules out the F18 5 amp fuse located in the elect box on the rt hand side. The early units had a single pressure switch up under the cab that could be jumped for testing, while the later had the four switches (two on each pedal valve for the travel) on those you disconnect wires 456 and 455 from the pressure switches and hook up a jumper wire to connect the 456 and 455. Turn the key on and turn off the drive brake, have a helper hold the hi speed solenoid while you move the hi speed switch. If the solenoid works recheck the pressure switches. If it does not work unplug the connect at the solenoid and hook up your volt meter while having the switch in high. if your not reading system voltage you have to start checking back threw the elect harness to find the cause. If it has current possible bad solenoid. The solenoids are the same and you could move the heavy lift over to the hi speed and also check it. Your using the jump wire for safety reasons on the pedal switches also so engine does not have to be running and working the travel pedals while climbing under and over things also.
Do you have any diagrams on how to do this thanks