Combines R52 not starting

We have a 1994 R62 with a similar problem. After playing around with the interlock switches without success, we now think it may be the starter relay, but haven't had a solid problem allowing confirmation of that. Perhaps related, this fall the starter locked on. We had to disconnect the battery cable to get it stopped. The problem wasn't just the starter itself since the fuel solenoid was also energized. We cleaned the ground connections, etc., but still have the occasional starting problem with a warm engine.

94 R62 also! Exciting isn't when the starter locks on! Fuel solenoid also energised but in our case the whole lot started to go up in smoke in the middle of a wheat stubble and 38 degrees C. There are 2 fuel solenoids in the one case on the cummins fuel pump. One is a pull-in solenoid and a second smaller hold-in solenoid. The wires between the two shorted out about an inch from the solenoids and started the fire. Got the fire out without causing any damage except to the personal composure! We found an identical replacement solenoid and while installing discovered the insulation around 2 of the wires, about an inch from the solenoid had been cut or broken which we believe allowed the wires to short and was probably the cause of our original short and fire. It looked to be a manufacturing fault and may have been common to a particular batch of solenoids. The wires are normally hidden under the flexible outer cover and the cuts would not be seen unless looked for. A check of the circuitry shows that a short between these wires pulls the main solenoid under the radiator in and then the starter solenoid. It may pay to check your solenoid wires for this fault.

Neutral safty switch is fastened to rear surface of transmission. If you could get it to bother you could hook both wires to same terminal and give it a try. Do not leave bypassed like this for I believe it disables park brake light on some machines not to mention starting while in gear. Otherwise there is a slave solinoid back in engine compartment near starter if Deutz equiped and I believe on engine frame if Cummins. Dirty starter or bad bushing in starter could cause it to be hard to engage also. Good luck