Dagwood11 0 #1 Posted 19 hours ago 1995 520 H 20 HP Onan motor. I am experiencing electrical issues on the start circuit. Started fine, pulled it out of the garage, put the deck on and go to start it, nothing. So far I have replaced the 3 relays under the battery tray, cleaned the relay blocks the best I could and bypassed the neutral switch (put a jumper between the brown and purple leads. All I get is clicking from the middle relay, that is the relay with the blue wire from the starter. I can start it by bypassing the blue wire to the starter and jumping the starter from the positive and the plug where the blue wire connects. So whatever the issue is, the blue wire is not getting power. Any ideas. It starts perfectly without any outside help other than jumping the starter with a jump wire. Share this post Link to post Share on other sites
953 nut 67,317 #2 Posted 18 hours ago This drawing shows all of the components of the Starting system. Take a look at it and if you have further questions or need help deciphering the drawing we can help you. Need to know if the blue wire is light blue or dark blue. Be sure the PTO is off and all connections are clean and tight. PS; safety switches or relays are seldom the problem but that seems to be where everybody starts. 3 Share this post Link to post Share on other sites
Dagwood11 0 #3 Posted 18 hours ago Thank you. I'm dumber than a bag of rocks when it comes to electrical/electronics. I don't really understand the schematic, all I can understand is that the wire to the starter solenoid is the one that has no power. How to test it, I have no clue. Where to start to test it, I have no clue. How to use a multimeter, I have no clue, but I do actually have a couple of them. Share this post Link to post Share on other sites
gwest_ca-(File Mod) 12,335 #4 Posted 18 hours ago Figure out how you can measure 12 volts DC (Direct Current). Your meter may show 100VDC which just means it will measure up to 100 volts. Ground the negative wire to a good chassis ground or battery negative. Now with the red test lead follow the power from the battery to the solenoid checking for battery voltage into each switch and out of each switch. There are notes in the schematic showing the state of the switches - operator in seat, pto off as examples. You are testing the start circuit so you may need a helping hand to hold the ignition switch in the start position. Notice the start relay gets it's power directly from battery + on a purple wire. The rest of the circuit controls what the start relay does. Wired like this so the start relay gets maximum power via a short cut without going through all the safety switches. Keep us posted on what you find and help will walk you through it. 1 Share this post Link to post Share on other sites
Dagwood11 0 #5 Posted 17 hours ago Thank you so much. I will keep you up to date. Share this post Link to post Share on other sites
Pullstart 70,525 #6 Posted 16 hours ago How are your grounds? Share this post Link to post Share on other sites
ri702bill 12,429 #7 Posted 12 hours ago That tractor should have "the dreaded 9 pin connector" in the wiring harness - a source of all sorts of electrical issues over time. Separate the halves and thoroughly inspect it for signs of corrosion & overheating. Repair / replace as necessary. My . 3 1 Share this post Link to post Share on other sites
squonk 47,313 #8 Posted 4 hours ago The 9 pin connector should have had a Joseph Lucas emblem on it ! Share this post Link to post Share on other sites
Dagwood11 0 #9 Posted 4 hours ago 12 hours ago, Pullstart said: How are your grounds? I have figured out a work around, for now at least, so I can at least get it running. When grass cutting season ends, I will go through and check ALL connections. Share this post Link to post Share on other sites
Dagwood11 0 #10 Posted 3 hours ago 8 hours ago, ri702bill said: That tractor should have "the dreaded 9 pin connector" in the wiring harness - a source of all sorts of electrical issues over time. Separate the halves and thoroughly inspect it for signs of corrosion & overheating. Repair / replace as necessary. My . I think the 9 pin is long gone, this may be the bottom half, I'm not even sure. I'm getting the idea that it is time for a rewire of the major circuits, like the starting circuit. I have figured a work around that allows me to start it, for now at least, and hopefully that will get me through grass cutting season. Share this post Link to post Share on other sites
gwest_ca-(File Mod) 12,335 #11 Posted 3 hours ago That looks more like the fuse holder. Click on this poor picture to see the complete diagram. You can also download the complete file from there. That is also where the start relay gets it's constant power from on the purple wire. Perhaps that connection has been compromised. The purple wire to the start relay should always have battery voltage - key on and key off. 2 Share this post Link to post Share on other sites
squonk 47,313 #12 Posted 3 hours ago 12 minutes ago, Dagwood11 said: I think the 9 pin is long gone, this may be the bottom half, I'm not even sure. I'm getting the idea that it is time for a rewire of the major circuits, like the starting circuit. I have figured a work around that allows me to start it, for now at least, and hopefully that will get me through grass cutting season. Those yellow connections ain't good! Share this post Link to post Share on other sites
Dagwood11 0 #13 Posted 3 hours ago 7 minutes ago, gwest_ca said: That looks more like the fuse holder. Click on this poor picture to see the complete diagram. You can also download the complete file from there. That is also where the start relay gets it's constant power from on the purple wire. Perhaps that connection has been compromised. I have no clue about how to even begin to understand that diagram . I'll look for the 9 pin again but I haven't seen anything other than the relays and that "fuse holder" looking thing. Where is the 9 pin supposed to be? Share this post Link to post Share on other sites
Dagwood11 0 #14 Posted 3 hours ago 19 minutes ago, squonk said: Those yellow connections ain't good! Everything you see is how I got it. I definitely have some rewiring to do. I think I found the 9 pin hiding under a bunch of electrical tape, definitely leaving that mess alone for now. I have figured a jump wire set up from the starter to the battery so I'll be wiring it like that with a toggle switch until grass cutting season is over. Looks like I have a winter project ahead of me, especially since me and electronics don't get along well at all. LOL! Share this post Link to post Share on other sites
squonk 47,313 #15 Posted 2 hours ago 15 minutes ago, Dagwood11 said: Everything you see is how I got it. I definitely have some rewiring to do. I think I found the 9 pin hiding under a bunch of electrical tape, definitely leaving that mess alone for now. I have figured a jump wire set up from the starter to the battery so I'll be wiring it like that with a toggle switch until grass cutting season is over. Looks like I have a winter project ahead of me, especially since me and electronics don't get along well at all. LOL! I 'm thinking the previous owner cut out the 9 pin. That doesn't look big enough to be it. 1 Share this post Link to post Share on other sites
Dagwood11 0 #16 Posted 1 hour ago 1 hour ago, squonk said: I 'm thinking the previous owner cut out the 9 pin. That doesn't look big enough to be it. Another reason I am leaving it alone for now. I don't need to make a bigger mess than I already have. Share this post Link to post Share on other sites
