71_Bronco 1,072 #1 Posted June 19, 2020 With my K181 out of my Commando 8, I was thinking about tidying up the wiring behind the dash. Have a new key-switch, new light switch, new LED tail light, and new bulbs for my generator lamp. If I recall correctly, I don't think the tractor has any fuses in it. 1.) Would it be wise to add fuses? or not really since there is no fancy electronics to fry? 2.) If I do add fuses, do they go between the battery and switch? Or between the switch and the item (like the lights for instance) 3.) What size fuses for each item? This will be my first time digging into a tractor wiring, but I am familiar with car wiring and the mess of spaghetti they have. Share this post Link to post Share on other sites
R Scheer 499 #2 Posted June 19, 2020 Add the fuses. Two reasons, one if you happen to get a short in your wiring the fuse will limit potential damage, melted wires, fires, that sort of thing. It also makes finding the short easier because it breaks your wiring into sections. If the fuse for your lights keeps blowing, you only have to look at the light circuit. 3 Share this post Link to post Share on other sites
953 nut 51,486 #3 Posted June 19, 2020 Presuming you are running the factory type ignition switch and have a S/G I would use a 20 amp fuse on the wire from the "L" terminal of the voltage regulator to protect the wiring on the lighting. Share this post Link to post Share on other sites
R Scheer 499 #4 Posted June 19, 2020 I always put my fuses before the switch, size of the fuse will depend on the wiring and the load. If I expect the load to be small, led lights for example, 2 A fuse is probably fine. If you have a multimeter you can measure the current the load draws and cuse accordingly. Share this post Link to post Share on other sites
71_Bronco 1,072 #5 Posted June 19, 2020 (edited) Tractor will be wired as it was stock, per the diagram below. The only thing added is the lights. I will be piggy-backing the power for the lights off the back of the lighter, as that's how the original installation manual called for (lights were an option on the Commando 8). Wasn't sure if I needed a fuse running to the coil from the switch or any other places. EDIT: Was also thinking about adding a starter solenoid as well to help protect the switch (even though it is one of the heavy duty switches) Edited June 19, 2020 by 71_Bronco Share this post Link to post Share on other sites
Ed Kennell 35,587 #6 Posted June 19, 2020 Add the starter solenoid. I never liked having 100+ amps flowing thru an ignition switch a couple inches from a fuel tank. 1 Share this post Link to post Share on other sites
Tractorhead 8,571 #7 Posted June 19, 2020 Whatever a reason causes, if a short or a fail is given, fuses protect your wire harness. So i allway‘s recommended use them. a normal gardentractor battery can provide few hundrets of Amps current. with about 80 Amp you can simply start Welding. When all is correct and if a wire is new and well insulated, nothing can happen as long as the wire is well dimensionated to the load. But if it get‘s older lightly scratches ( what shall allways prevented) a wire can get blank and that‘s a uncontrolled Weakpoint. Still the smooth shaking of an idle engine can happen, that a cable tents to short to any Ground. a fuse i a cent part, that can prevent your tractor for burning down, if such a scenario happens. or if maybe a part shake itself loosen and falling on a power Wire. I also protected my Starterwire from Battery to solenoid with a mrbf fuse. they be available from 30 A up to 300 A and can also be used in a Truck. The fuses you shall use are depending on current, load and AWG and the cable lenght. There are few thumb rules to dimensionating on your garden tractor. charging (15A) charger system can be protected with a 20A. lights (Headlight 2x10W + Taillight 2x5W) will be good with a 10A Ignition will be protected with a more solid fuse, because the coil have a short time heavy load when the coil is initiating the magnetic field short befor release to spark that‘s mostly about 25 A to resist that Load PTO( electric) mostly drops somewhere about 10-15A shall protected with 20-25A this are just few values to give you an idea how to dimensionate. Thumb rules for fuses up to a lenght of 4 m Wire the AWG - The fuse max. # max. Cont. Load AWG 2 - 200A # 180A AWG 3 - 150A # 130A AWG 7 - 70A # 60A AWG9 - 50A # 45A AWG13 - 25A # 20A AWG15 - 15A # 12A AWG18 - 10A # 8A Share this post Link to post Share on other sites
