motox25 36 #1 Posted October 4, 2014 I tore into the patched and rigged electrical system on my 520H to fix it right but have ran into an issue. When I bought the tractor the tan wire going from the key switch to the light console had been cut and rerouted to the blue wire going to the starter so obviously the PO was having problems with the electrical system. The tractor ran fine but my tach and volt gauges were not working. I have replaced the 9 pin connector and reattached the cut tan wire to the light console. I have temporarily bypassed my broken seat switch and PTO switch. The only switch left is the motion control switch but it appears to be working, when the motion control lever is engaged and I try to start the tractor the light turns on the console and goes out when I return to neutral. I have verified I have 12 volts going to my starter on the red wire and 12 volts going to the coil when the key switch is on. I see on the electrical diagram the tan wire from the key switch goes both to the start relay and the light console. Im stumped at this point and not sure if I'm dealing with a bad relay, light console board, or something else. Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,393 #2 Posted October 4, 2014 Sounds like the motion control switch is the neutral switch and it is working correctly. You are trying to start it not in neutral and the light is telling you that is the problem. What is you model number so we can look at the correct wiring diagram? The idiot light circuit board will not affect any circuit if it is not working correctly unless it is shorted and blows a fuse. Garry Share this post Link to post Share on other sites
motox25 36 #3 Posted October 4, 2014 (edited) Ok so if my idiot light circuit board is bad it wouldn't cause the tractor not to start? Ive also checked all the fuses and the key switch was replaced when I found it was keeping my gauges powered on all the time. Im going to replace my relays then and see if this resolves the issue. Those relays are in a terrible place to reach, I think I'm going to put the new ones behind the dash so they are easier to access. Edited October 4, 2014 by motox25 Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,393 #4 Posted October 4, 2014 If the relays are the same just switch positions to see if that makes a difference. Some models use 2 of the same relays. I doubt you would have 2 of them fail at the same time. Garry Share this post Link to post Share on other sites
km3h 543 #5 Posted October 6, 2014 You should download the Demystification Guide from the manuals section. Check the fuses for corrosion. You may not be getting enough amperage to the blue wire going to the solenoid. Share this post Link to post Share on other sites
motox25 36 #6 Posted October 7, 2014 I downloaded the guide and it has been very helpful, thank you. I found at least one of my problems, when removing the relays to clean the contacts I found 2 loose wires and some corrosion. I am going to get that cleaned up this weekend and see if this fixes my problem. If not I'll start tracing the tan wire now that I know it should carry 12 volts of current through the system with the key switch on start. This electrical system seems overcomplicated to me, is 3 relays really necessary? I just don't understand why the 12 volts supplied to the tan wire can't be passed straight to the blue wire on the solenoid instead of passing through 2 relays first Share this post Link to post Share on other sites
motox25 36 #7 Posted October 11, 2014 Today I replaced 2 bad terminals on 1 of the relay connectors and replaced the relays and it starts! AND I have a working vacuum gauge, tachometer, hour meter, and fuel gauge! Thank you to everybody who helped. I'm still not showing any voltage on my voltmeter, I plan on checking the red wire on the voltage regulator to see if its sending voltage. Share this post Link to post Share on other sites
Save Old Iron 1,571 #8 Posted October 11, 2014 see if you have 12 volts at the voltmeter pink and black wires you have voltage at the gauges if the tach works the voltmeter watches rhe PINK wire 2 Share this post Link to post Share on other sites
km3h 543 #9 Posted October 11, 2014 Don't you just love it when you find answers to these kinds of problems. Trouble shooting electrical problems are always a headache. Especially since the 520 has a maze of wires going in all directions and circuits all seem to be interconnected. 1 Share this post Link to post Share on other sites
motox25 36 #10 Posted October 13, 2014 I have a working voltmeter, ended up cleaning and tightening the connections on my voltage regulator. It's nice to have a full set of working gauges again and feels like quite an accomplishment to have finally figured out the electrical system on a 520H! Thanks again for your help everyone. 1 Share this post Link to post Share on other sites
