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Robocopywriter

Not an electrician

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I've been trying to set up my 02 with LED headlights that have an operating range from 9 to 16 volts.  The low beams light but not enough to be visible until they have been on for about 10 minutes then they come to life (both lights acting the same at the same time).

 

The circuit at the bulb, at the relay, and at the 2 headlight fuses when tested show 8.2 volts (just not enough).

 

But if I pull the connector off the back of the fuses and check the solid yellow wire it reads a full 12.5 volts (battery power only).

 

With the fuses removed both positive fuse terminals read 12.5.

 

With either fuse removed the reading drops back to 8.2.

 

Grounds have all been replaced and are 100%.

 

Can anyone tell me what the solution is?

 

TIA

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Are the fuses you refer to the original low beam fuses in the car's fusebox (presume this is a squarelight, with separately fused low beams).  If that's the case....those cartridge fuses actually wear out (besides corroding), so try cleaning the spring brass fuse clips and installing new fuses; see if that helps.  

 

If the new headlights have their own fuses, please advise so we can provide further guesses, uh, ideas...

 

mike

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45 minutes ago, AustrianVespaGuy said:

What are the voltage readings with the regular halogen or sealed beam bulbs in there instead of the LEDs? Same or different?

Same as the battery.

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So let's recap. 

 

A voltage drop indicates an "open circuit," right?  

 

On my 12 fuse system, there is a solid yellow wire that is a 100% closed circuit to the fuse box connector from the switched relay.  That connector feeds 2 fuses and two separate wires, one to each low beam. 

 

The connection between the relay wire and the fuse box is good, because if I remove both fuses there's a full charge at both the positive poles on the fuse mounts.

 

If I insert EITHER fuse both poles drop to 8.2 volts, which is weird because it seems like two wires with exactly the same problem. (Or is there something about electricity I don't understand lol).

 

If one of those wires (driver: yellow and black. passenger: yellow and blue) is not properly connected somewhere will that cause both to act the same?

 

A three beer imoji to anyone who can solve this riddle.

 

 

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They both drop to 8V because there is some sort of load in the circuit which pulls the voltage of the whole thing down; remember they're both supplied by that same solid yellow wire.  Clearly there's something wrong, so here's how you go about finding it:

1.) Unplug both headlight bulbs.

2.) Recheck voltage at all the points you previously measured.  With the lights switched on, is everything now at 12.5V?

-> If 12.5V, then there's something wrong with the bulbs.  Check them each individually to see if it's just one or both.

-> If still 8V, then the issue is not with the bulbs and instead with the wiring.  Start by unplugging either the yl/bk or yl/bl wires from the back of the fuse box to see if you can isolate the problem to one of those wires.

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Oh, and I might have just had an idea: what are your HIGH beam bulbs?  Also LED? The way the 2002 is wired, the headlight relay coil is grounded THROUGH the high beam filaments - this is why the low beams turn off whenever you turn on the high beams.  With the high beams off, the purple/white wire should be very close to ground/0V.  But when you turn them on, that wire now has 12V, and this also turns the low beam relay back off.  But that ground path for the relay was intended to go through the high beam incandescent filaments, so if those are now LED circuitry, yeah it would do something screwy/bad with respect to the relay. . .

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