Headlight and tail light voltage at socket only 4v

Discussion specific to the 1995 - 2006 KDX200 (H Series) and 1995 - 2005 KDX220R (A Series) models sold in the USA
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kdx220r_02
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Headlight and tail light voltage at socket only 4v

Post by kdx220r_02 »

I’m trying to figure out what the spec for the head light and tail light voltage should be at the socket before i go and buy new bulbs and a new headlight shroud. the headlight shroud was smashed by previous owner and he claimed the lights worked before the crash. however i checked the tail light bulb and found the bulb to be burnt out, i checked the voltage at the switch and found to have 36 before the switch and 4 volts at the socket when the switch was turned on, found 0 bolts at socket when switch was turned off, i want to know what the correct voltage should be at the head light and tail light socket should be before i order parts and waste money, thanks in advance
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SS109
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Re: Headlight and tail light voltage at socket only 4v

Post by SS109 »

Something doesn't sound right. IIRC, whatever goes through the switch is what you should see at the socket. I would hook up your multimeter to the taillight circuit, start bike, measure voltage at idle and then see if it goes up when the engine is revved.
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kdx220r_02
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Re: Headlight and tail light voltage at socket only 4v

Post by kdx220r_02 »

i’ll check that when i get off work, im thinking the voltage regulator is bad, i have 4v at the socket on both headlight and tail light, i have 36v at the switch on the red side after the switch, and 0v when the switch is off at the same red connection, im wondering how to test if the voltage regulator is bad

edit: i have 4v at idle and it’s on both the headlight and tail light, i don’t want to replace the voltage reg. due to the fact it’s almost 200$
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Re: Headlight and tail light voltage at socket only 4v

Post by SS109 »

You can use a universal AC voltage regulator like from Baja designs and they are only about $30. Here is a search link: https://www.google.com/search?client=fi ... +Regulator
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Re: Headlight and tail light voltage at socket only 4v

Post by bufftester »

Voltage will be lower at idle, it should not climb much over 12 volts when you rev it, thats the easiest way to check your voltage regulator. It won't keep the voltage from being low (which is why the lights are dim at idle) but will keep you from blowing out bulbs.
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Re: Headlight and tail light voltage at socket only 4v

Post by Chuck78 »

Voltage varies SUBSTANTIALLY between idle, 1500rpm, 3000rpm, & 7000rpm. It's only a 35W stator, it barely powers dim incandescent lights. I ran into a wire roll type fence on my 1st KDX because the lighting output was so dim with the stock stator.

If you were getting 36 volts after the regulator, you would blow your light bulbs unless there was a problem with the wiring somewhere that wasn't getting 36 volts to the light bulbs.

You said something about getting 4 volts to the light bulb socket with the switch on, but 0 volts with it off? Your readings leave a bit of information out that is critical, & you didn't mention any voltage reading on the output side of the switch. Are you sure you are testing on AC voltage and not DC on your meter?
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