On the John Deere 35D (low serial 235xxx), I'm getting no power to the starter, and am tracing the wiring. Based on the schematic wiring diagram on page 9015-10-7 of the Operations & Tests manual (TM2264) I'm expecting the red wire on the X36 plug into the K2 starter interlock relay to show 12 volts, but I get zero. According to the schematic, it appears to go straight back to the battery, but through connector X3. I can't find X3. The diagram on page 9015-10-58 (of same manual) suggests that it is under the front left corner of the cab, but I can't find it. Of course that area is quite inaccessible (I have full cab). Can someone tell me: a) Am I correct about expecting 12 volts on X36 plug red wire? (Looks to bypass the key) b) Where is plug X3 that feeds the red wire?
Oops. That's manual TM2263.
I didn't have much time to dig this morning, but try comparing the W8 and W9 wiring diagrams vs the schematics. I think you might find some differences in the wire colors. One of which is the battery wire is white/red to the K2 relay.
@mg2361 thanks for the tip about W9. Problem solved. Here are the details for anyone interested: When the key is turned to start, power goes to the K2 relay, which connects together the red and the white/red wire. 12 volt unswitched power comes in on the red, and the white red goes to the starter solenoid via the X3 connector. The X3 connector is located under the left front corner of the cab, easily accessible by removing the front corner cover. They are immediately to right of the two grease connectors. There are three connectors there, and X3 is the one with the large red and white/red wires. In diagnosis, I was able to confirm that 1) 12 volt power was coming through X3 all the way to the K2 relay. Initially I was looking at the wrong pin. The picture of connector X36 (K2) on the third page of the W9 Platform Wiring Harness (page 9015-10-137) was helpful in identifying pin 2 as the correct pin. 2) There is continuity on white/red wire between the X36 connector and the X3 connector. 3) There is a problem on white/red wire between the X3 connector and the starter solenoid. Instead of being shorted, the connection showed about 300 ohms. To fix the problem I ran a new white/red wire between X3 and starter solenoid. I put the wire inside a loom to protect it.