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Discussion Starter · #1 · (Edited)
Hey all,

I have an LTR 166 and I cant seem to diagnose why the headlights just failed. I was mowing late and the lights would turn off and back on sporadically until they wouldnt turn back on at all. Its not the bulbs. I had installed a new ignition switch (aftermarket, for what its worth) within a couple months. All the wiring and connections I can see without tearing the whole thing apart look fine, but I assume it must have been a loose connection somewhere. Im not great with electrical.
 

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It has the 4 way switch you would turn one click back once the engine is running.
Okay. When you turn the key on (shouldn't need engine running) to the lights on position you can use either a test light or a meter to check power and ground at the headlight plug - the one you'd disconnect to remove the hood. If they're both good, test the sockets (and check the bulbs - maybe they're just burned out). If it's not good there, check at the back of the key switch.


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Discussion Starter · #5 ·
Okay. When you turn the key on (shouldn't need engine running) to the lights on position you can use either a test light or a meter to check power and ground at the headlight plug - the one you'd disconnect to remove the hood. If they're both good, test the sockets (and check the bulbs - maybe they're just burned out). If it's not good there, check at the back of the key switch.
Thanks a lot. I needed an excuse to pick up a meter anyway. Would that be the "end" of the circuit? At the ignition switch? The switch is only a month or two old but it is aftermarket so Im wondering about that as well.
 

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Yeah I'd say that's the "end" of the circuit. It provides power for the lights, goes along the harness to the plug near the engine, then up to the sockets, and all the way back again on the ground wire.


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I'd start with checking all fuses. Then a tester at the switch end of the circuit. At every point of connection, the switch, the wire harness, the lamp sockets. You have to confirm both power in and power out of each item.

I had a ground failure on my headlights just this week and had to track it down. Had power on the positive side, but checking the +/ - across the bulb bases, there was no ground. Turned out is was a corroded and loose pin in the 2 wire headlight wiring harness under the hood. Cleaned it up and reconnected, all is well. A little electric grease is probably a good idea on those connectors.

If you find your problem, please let us know what it was.
Good luck.
 

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There should only be one main fuse for the entire thing. It is possible JD stuck fuse links in there as well, but there is no separate headlight fuse.


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