Ed Gervasi 0 #1 Posted October 20, 2020 Folks; I purchased a 520H and see it is not charging. As I look at the harness and talked to a friend with several WH tractors. I look at my harness and see from the 9 pin connector, the yellow wire on the dash side is connected to a red wire and it connects to the center post of the regulator I just paid $60 from Onan. Now I have several questions . Where does the red wire go to from the center of the regulator. As of now as I said it goes to the yellow wire on the 9-pin connector. Where does the yellow wire goes to the 30A fuse and the tach regulator . God knows where this located is and what it looks like. My tachometer does not work and am wondering if this is related. Share this post Link to post Share on other sites
gwest_ca-(File Mod) 10,876 #2 Posted October 20, 2020 Welcome to the forum. Do you know what year it is or the tractor model and serial number? Need to look at a wiring diagram. Garry Share this post Link to post Share on other sites
WHX?? 47,854 #3 Posted October 20, 2020 What year Ed and will get you a wiring diagram. The center post on the regulator is charge to the battery through the nine pin and a fuse. The two outside go to the stator for ac power. Check the nine pin carefully. This and the fuse block is where most electrical trouble starts on Onan powered the tach is connected to either one of the outside posts. I have had good luck with the $20 regulators off the jungle site. Good troubleshooting guide in this manual. 492-4006 Onan P216 P218 P220 P224 SM.pdf 1 Share this post Link to post Share on other sites
lynnmor 7,216 #4 Posted October 20, 2020 Download the Demystification Guide, and an Owners Manual. After reviewing it, come back if you still need help. Many of these tractors are molested by previous owners that have no clue. 1 Share this post Link to post Share on other sites
953 nut 54,145 #7 Posted October 20, 2020 Most electrical problems on a can be corrected by cleaning and tightening ALL electrical connections including grounds. The fuse holders are near the battery and the sulphuric acid fumes from the battery being charged can cause unseen problems. Good luck and remember, Share this post Link to post Share on other sites
Horse Newbie 7,002 #8 Posted October 23, 2020 (edited) So guys since this thread is about wiring issues, and I have been doing some rewiring work on my 520H, please allow me to ask a question or two and it may help me as well as somebody else. I will attach one pic I took(I plan to attach more later) I basically traced 99% of the wires on the tractor, cleaned all terminals, cleaned all brass nuts on the back of gauges, put all connections back with dielectric grease... I concentrated special interest and care on the 9 pin and the 30 and 25 amp wires. I replaced the 30 amp charge wire from the B+ on the regulator with 12 gage stranded copper with new terminal. I replaced the 25 amp wire from the fuse block to the positive post(battery) on the starter. Both the wires were taken out of the 9 pin and run seperate 1because of the way their sockets looked on the 9 pin. Here is my question if you will kindly look at the pics. Is this wiring diagram correct at the fuse block for my 1994 ? I do not want to put power to it until I hear from some of you. Edited October 23, 2020 by Horse Newbie Share this post Link to post Share on other sites
Chestnut 315 #9 Posted October 23, 2020 Welcome to the forum! I just "woke up" the 520H I use for blowing snow and noticed the same problem. I haven't been able to dig in and figure out what's going on with mine, but I saw another thread in "wheel horse electrical" titled "520H not charging" that has a lot of information on the same topic. I was able to download the wiring diagram from the manuals section of the forum. 1 Share this post Link to post Share on other sites
Horse Newbie 7,002 #10 Posted October 23, 2020 (edited) Welcome to Red Square Ed ! Edited October 23, 2020 by Horse Newbie Share this post Link to post Share on other sites
Horse Newbie 7,002 #11 Posted October 23, 2020 8 minutes ago, Chestnut said: Welcome to the forum! I just "woke up" the 520H I use for blowing snow and noticed the same problem. I haven't been able to dig in and figure out what's going on with mine, but I saw another thread in "wheel horse electrical" titled "520H not charging" that has a lot of information on the same topic. I was able to download the wiring diagram from the manuals section of the forum. What year is your 520 Chestnut ? Share this post Link to post Share on other sites
Horse Newbie 7,002 #12 Posted October 23, 2020 @Chestnut is your 520 still wired mostly the way it was born ? Share this post Link to post Share on other sites
Chestnut 315 #13 Posted October 23, 2020 Hi Newbie, I actually have two. I'm about 2000 miles away from them right now, but if memory serves, one is a 1991 and the other about 1995. One has the snowblower and the other a loader. The one with the loader has no wiring changes, the one with the snowblower (older) has some changes. I haven't dug in yet to see. I was interested in the comment in the other thread about bypassing the connector to wire like the '88-89 models did. I can't confirm whether the wiring in your photo is right. Share this post Link to post Share on other sites
Horse Newbie 7,002 #14 Posted October 23, 2020 (edited) 7 minutes ago, Chestnut said: Hi Newbie, I actually have two. I'm about 2000 miles away from them right now, but if memory serves, one is a 1991 and the other about 1995. One has the snowblower and the other a loader. The one with the loader has no wiring changes, the one with the snowblower (older) has some changes. I haven't dug in yet to see. I was interested in the comment in the other thread about bypassing the connector to wire like the '88-89 models did. I can't confirm whether the wiring in your photo is right. Thank you for the info. I used new wires, and did go through the fuse block, and stuck to the wiring diagram I posted from the manual. I mainly did this to try to keep the tractor close to spec to maybe make it easier on any possible future owners. Main thing I think I did to help was to step up the 30 and 25 amp wires to 12 gage. Edited October 23, 2020 by Horse Newbie Share this post Link to post Share on other sites
gwest_ca-(File Mod) 10,876 #15 Posted October 23, 2020 According to the Demystification Guide the 1991-1997 520-H wiring is the same. The same operator manual was used 1993-1996 so that also indicates the wiring is the same because it includes the same wiring diagram. Some illustrated parts lists also include the wiring diagram. The Demystification Guide wiring for this model is very poor quality so I used a better copy from one of the manuals to color. The wire colors on the engine side of the 9-pin connector may not be correct because they are not included in the diagrams. I extended the colors from the main harness to simplify tracing. Onan alternator output is 20 amps so why the 30 amp fuse is used for protection. The shortest least complicated path to the battery is key to a long life. Under normal conditions the 20 amp output likely only occurs after a start as the system tries to replace what the starter removed - the single largest load the battery will ever see. The weak link is the terminals used in the 9-pin connector. Garry 1 Share this post Link to post Share on other sites
