Tractor Repair: mx120, solenoid coil, broken wires


Question
I have problem when shifting to forward with the F-N-R. The tractor will not go into forward orange light with the N in it will flash until I shut tractor off and restart. The tractor will go in reverse fine. I have checked the seat switch and bypassed the switch.

Answer
Hello,

 If the seat switch is bad or the wires are broken, the tractor won't move in either direction.

  To find the problem the quickest, you will first need to retrieve any fault codes that may be stored in the F-N-R/pto controller.  To get the codes, you will need to remove whatever you used to bypass the seat switch.  You can just leave it disconnected, or if you hook the seat switch back up, you will have to stay off the seat to get into the code retrieval mode.  Also, if the pto switch is bad, you won't be able to get the codes.  Turn the pto switch on, stay off the seat, and turn on the key switch.  The green light next to the pto switch should begin to flash a 2 digit code.  It will be a series of flashes (the first digit) with a pause in between, then another series of flashes (the second digit).  To move on to the next code, turn the pto switch off and back on.  Keep doing this until you reach the end of the code list at which time the green light will stop flashing and will stay on.  The most likely cause of the problem is a bad forward solenoid coil on the F-N-R valve under the rear of the cab.  One of the codes will probably mean a problem with the forward solenoid circuit.  The forward and reverse solenoids are on the left side of the valve as you view it from behind the tractor.  The MFD (if equipped), and diff lock solenoids are on the right side.  The coils are all the same, so they can be swapped to verify if that is the problem.  Also check the wiring for loose or broken wires and that the connectors are plugged in firmly.  I don't have a list of what the codes mean here with me, but you can either do a follow-up on this question and furnish me with the codes and I will look them up, which will take an extra day, or you can ask a CaseIH dealer.  If they have a chance to sell you parts to fix it, they will be willing to help.  To erase the codes, you must keep checking codes until you reach the end of the code list as describe above, then turn the pto switch off and on 3 times ending with the switch in the on position again. (off, on, off, on, off, on)  The green light will flash once, meaning the codes are erased.