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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.

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

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

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.

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

Steve

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 .

maillemaker said:

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

Click to expand...

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

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

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

Last couple of pages of the manual.

I got my sprayer hooked up. Works great!

I just went and checked again - no schematic in the owner's manual.

Try this, don’t know what I did wrong the first time. https://c.searspartsdirect.com/lis_png/PLDM/P0701111-00011.png?wid=150&hei=150&resMode=sharp

Thanks that looks like it! Strange that it looks like AC goes to charge the battery?

The charging system is not on that schematic, which is for the tractor. Trace the red wire you posted in post number 3, it should lead to the battery. Might be connected to the battery cable at the solenoid.

What? Maybe my eyes are lying to me then.

From what I see it is the Briggs 3 A charging with a separate AC for lighting.

Your eyes are good, mine are bad. Had macular eye surgery to repair a macular hole four weeks ago and focusing is not my strong suit now. Sorry

Now if it is was a poisonous snake it could have bit you. Got to slow down especially reaching inside those mowers. Don't want to get another surprise like last week with a snake in there here.

keakar said:

the red wire with the diode on it is to charge your battery and shouldnt have anything else connected to it

Click to expand...

I am confused here to the "diode" you speak of.

Are you talking about this thing? The red crimped-on thing is just a crimp connector I used to re-splice the cut wires.

Just got to remember that the dual stator used here will only give 3 amps DC max charge current @ 3600 rpm. Now of you can add a 790292 voltage regulator and that increase the amps to 5 amps max.

Of course the stator can be change to a higher current version and a voltage regulator added. Just depends on what you are will to spend to do this.

OK after carefully examining the schematic I think I see what you are talking about with the diode. Evidently the diode prevents alternating current and so you get intermittent DC current.

The diode is not my red crimps, the diode I think is under the shrink tubing here:

Correct it is a half wave rectifier setup with the battery acting as a smoothing capacitor.

Sounds like if I hook up a multimeter from the red wire to ground I should see DC current if my multimeter is set to DC. If I set my multimeter to AC and it detects a voltage on the red wire then it would mean the diode is bad. Sound right?

The last time I tested this (page 1) I was getting 16.8 VDC off the red wire. But I'm not seeing that at the battery. So, there must be a break somewhere I'm guessing and I'm only running off the battery.

From the schematic, it looks like the charging circuit goes all the way back to A1 on the ignition switch, so should detect ~16 VDC there if I have it at the red wire plug by the engine.

No you would still see an AC as it is a half wave circuit. You just will not see the full AC voltage just the ripple voltage. It just easier to see what the waveform is by using an oscilloscope but very few shops even have one as they mostly used in electronics shops where we looking for noise and other problems on a signal waveform.

I had done some googling and it said if you have a multimeter set to DC and try to measure AC you will just get zero?

Maybe this manual will be of some help to you. https://www.briggsandstratton.com/c...a/en_us/Files/FAQs/alternator_replacement.pdf

Very nice manual, thanks!