Wiring a 12 volt sprayer by connecting to utility wire under seat

rsmith02184 · Sep 18, 2011

Well the fuse panel only has 4 fuses in the block and they are all 15 amp.

The wire that I am splicing into is only one side (one light) of the two utility lights...is that not enough amps? You mention that if it is designed to power 2 lights, it should be all right but the wire I am using is only designed to power 1 light.

whistlepig · Sep 18, 2011

A twenty gallon sprayer is no big deal. You want to wire it so its not hot all the time so it doesn't drain your battery. Go to the auto store and buy a tester that looks like a screwdriver with a needle point on the end. Attach the ground on this tester to the frame and start poking wires with the needle point. When you find a wire that's hot with the key on and not hot when the key is off splice the hot wire of your sprayer in to it.

k0ua · Sep 18, 2011

rsmith02184 said:
Well the fuse panel only has 4 fuses in the block and they are all 15 amp.

The wire that I am splicing into is only one side (one light) of the two utility lights...is that not enough amps? You mention that if it is designed to power 2 lights, it should be all right but the wire I am using is only designed to power 1 light.

Well, its "iffy" a single aux lamp is usually about 55 watts so a little less than 5 amps. you state your findings about the pump are its draws about 7 amps. The point would be the circuit may only be designed to support the 1 lamp or about 5 amps. The fusing is OK, but there are liable to be other things (likely lights) on this same circuit. Did you say you had the wireing diagram? If so check what else is on the circuit. If nothing else is on this circuit and it is fused for 15 amps, go for it. but if other things are on the circuit it would be possible to blow the 15 amp fuse, might not happen but it could. I would think that would be the worst thing that would happen. If the wire is 18 guage or larger, it should be ok for a short run like is in the tractor. So maybe just give it a try. Of course the idea of running you own wire and fusing at the source is also a good one. Also the key idea is a good one. One way to acheive both is supply your own relay and any switch's on the dash you may want to control it. and power the coil of the relay from a "hot" connection that is only hot when the key is on, (see Whistlepigs last post for method to find it) and let the contacts of the relay provide battery power when the relay is energised. Be sure to fuse the battery lead at the battery with an waterproof inline fuse. If you do this then you have the best of both worlds, a dedicated battery supply that is controlled by having the key on, and also a dashmounted switch to pressurize the sprayer only when you want. My sprayer had an inline switch right at the connecton to the tractor I could reach from in back of the seat, and that worked for me. BUT my sprayer draws less than 4 amps, and I knew for sure.it would not overload the Aux lighting circuit. I can draw up a schematic if you need it.

James K0UA

whistlepig · Sep 18, 2011

Do the poking thing with a tester. Your tractor will not disappear in a mushroom cloud by doing so. At worst you may blow a fuse.

rsmith02184 · Sep 19, 2011

Well I am not the greatest with electricity but I do own a tester or as whistle pig says. "a screwdriver looking thing with a needle on it". I know what branch powers the utility light by putting my dc volt tester in the plug and turning on the key. Like I said earlier, ingot 12 volts with the key on...zero volts with it off. Also, the wire going to the sprayer has a switch that I would turn on when I want the power to get to the sprayer.

So, if the worst that can happen is I blow a .10 cent fuse, then I am going to go for it.

k0ua · Sep 19, 2011

rsmith02184 said:
Well I am not the greatest with electricity but I do own a tester or as whistle pig says. "a screwdriver looking thing with a needle on it". I know what branch powers the utility light by putting my dc volt tester in the plug and turning on the key. Like I said earlier, ingot 12 volts with the key on...zero volts with it off. Also, the wire going to the sprayer has a switch that I would turn on when I want the power to get to the sprayer.

So, if the worst that can happen is I blow a .10 cent fuse, then I am going to go for it.

Agreed, move forward, if it blows the fuse, we will do something else.

James K0UA