Need help with wiring harness from engine.

[maillemaker]

I have a Craftsman LT2000 riding mower.
Model Number: 917.287070
Serial Number: 080907D019984

I purchased the mower new about 10-12 years ago. Shortly after I bought it, someone tried to steal it from my back yard. They had cut the wiring harness shown in the picture below. I assume they were trying to hotwire it.

I took a stab at wiring it back up, but could not be sure I did right. Mower has seemed to run fine all these years, but I do notice sometimes my battery goes dead from season to season. I just assumed my battery got old.

Also, my headlights do not work, and I'm not getting any power from the leads that go to the headlight switch.

I have recently bought a pull-behind garden sprayer, and I wanted to make sure I was getting good power from the battery for it.

When the engine is running, I get about 12.6 volts, the same as when it is not running. So, I think I may not be charging my battery.

Can anyone tell me if I have the correct wires below (see the red splices) with the Red and Black wires coming from the engine?

Thanks.

 

[bertsmobile1]

The first thing to do is check the diode
Poke a pin through the red wire between the plug and the engine
Then check for continuity between the pin and the terminal in the plug
With the leads connected one way you should get an open circuit and when reversed you should get a closed circuit,
The diode is a one way valve for electricity so it only allows the + side of the alternator output to go back to recharge the battery.
The - side is blocked and burned up as heat so eventually they just burn out .
Test the black wire with the engine running this time.
It should read around 12 V AC +/- 2 V .
AC will not charge a battery in fact it will destroy it over time .
Thus the lights wire should connect only to the L terminal on the key switch ( they are marked ) and it actually grounds the black wire to turn the lights on.
If it is connected correctly the lights should go from dim to bright as the engine goes from a low idle to full speed.
So on your mower that black wire should go from the alternator directly to the headlamps then from the headlamps to the key switch and the key switch to ground to complete the circuit.

The other test is to disconnect the alternator plug, start your engine then measure from the red terminal to ground.
You should see around 13 to 14 V DC at full speed

 

[maillemaker]

Do I test the black wire to ground?

I disconnected the plug at the engine, and tested each pin to ground.

The red wire is giving me 16.8 VDC to ground.
The black wire is giving me 15.5 VAC to ground.

Steve

 

[maillemaker]

Well, it must have been wired right, because I reversed the wires, and it ran about 2 seconds and shut down. Blew the fuse.

I can't really trace where anything goes as it's a dirty rat nest and half the harness is hidden inside tubing.

 

[maillemaker]

Ok I replaced the fuse, and it runs again, as shown wired up above (original and with alligators - it's the same).

Steve

 

[bertsmobile1]

The black wire with AC output is for the headlights.
Usually it goes directly to the headlghts and the ground wire is the one that gets switched on & off.
Thee should be a wiring diagram in the back of the owners manual .
The new owners of Sears seem to have removed the old manuals from thei web page but generally you can find them on places like manuals library .

 

[keakar]

Do I test the black wire to ground?

I disconnected the plug at the engine, and tested each pin to ground.

The red wire is giving me 16.8 VDC to ground.
The black wire is giving me 15.5 VAC to ground.

Steve

the red wire with the diode on it is to charge your battery and shouldnt have anything else connected to it
the black wire, which is orange on most engines, is for the headlights and power for any accessories

your headlights might not be working because the vibration makes those bulbs go out all the time, im shocked to ever see them work, but they should have power to them only when the engine is running

 

[Rivets]

You can find a schematic for your tractor on this website with your model number. https://www.searspartsdirect.com/mo...man-917287070-front-engine-lawn-tractor-parts

 

[maillemaker]

OK, I wired it back the way it was before it blew the fuse, and the headlights actually do work. Switch is just crusty, I guess - when I flick it on and off sometimes it does not turn on sometimes it does - but it's the switch. When the lights are on, they dim/brighten with engine RPM.

So, I guess everything is working fine.

My main concern here is I just bought a pull-behind weed sprayer to do my own lawn spraying. I am wiring up a trolling motor connection plug and switch right now. This will obviously be pulling from the tractor battery. I wanted to make sure the battery was actually being charged. When I measure the battery positive to ground while the engine is running, I'm only getting about 12.9 VDC. I assumed it would be 14 VDC or so like a car.

I did not see a schematic in the owner's manual for my tractor last time I went and pulled up the schematic.

Steve

 

[Rivets]

Last couple of pages of the manual.