Ok.. i have a 2002 cavy... so it has the single bulb headlights... with 2 filaments per bulb. and three wires in the harness.
I would ASSUME that the 3 wires are :
1. hi beam 12v+
2. low beam 12v+
3. ground (12v-)
But when i test this theory with a single filament test bulb, i get some odd results.
1. when i use #3 and #2 and put on low beams test bulb comes on fine.
2. when i use #3 and #2 and put on DRL test bulb does not light.
3. when i use #3 and #1 and put on High beams test bulb comes on Dimly.
So just makes me wonder if i have things mixed up... and if this is not so simple as it seems.
and is the wiring situation the same for the dual filament turn signal/parking bulbs?
I would just like to be able to convert from these dual filament bulbs to seperate bulbs and have everything still work like stock.... with no service lights or anything....
Are you doing a headlight swap? This being the reason for wanting to switch to a single filament bulb? Or are you wiring up HIDs?
Our Headlight systems are ground controlled. So you have:
-High Beam Ground
-Constant 12v
-Low Beam Ground
and the turn signal bulbs aren't the same. They operate on a single ground with 2 switched power sources.
As much as I don't want to offend anyone, this is how people eff things up. They don't understand the things they are messing with and could cause some major issues. If you have a Haynes manual you could have easily went into the wiring diagram and seen this as well(giving the fact you know what your looking at, in this case maybe you shouldn't be messing with the wiring till you learn on reading wiring schematics.)
This isn't directed to you, just a general statement that people need to understand that I'm hoping will come up in searches etc(Topic having "how are" should be common enough lol)
Edited 1 time(s). Last edited Saturday, May 30, 2009 6:56 AM
Stephen (manta z) wrote:
Our Headlight systems are ground controlled. So you have:
-High Beam Ground
-Constant 12v
-Low Beam Ground
Correct. Most people assume they work off of switched positives, but they don't.
yepp. most gm vehicles 2000+ work off switched grounds for almost everything.
Stephen (manta z) wrote:Are you doing a headlight swap? This being the reason for wanting to switch to a single filament bulb? Or are you wiring up HIDs?
A little bit of everything.... I am doing a number of different conversions involving lights and turn signals... Possibly HID's Wiring different style turn signals. and yes, doing a headlight swap that uses separate high and low beams. I would also like to move my DRL's off the headlights, and to a separate circuit, but i dont think that is possible or easy. And i am trying to convert and add on to my turn signals and parking lights. Again getting away from a single bulb with dual filaments and using 2 different bulbs.
Stephen (manta z) wrote:Our Headlight systems are ground controlled. So you have:
-High Beam Ground
-Constant 12v
-Low Beam Ground
and the turn signal bulbs aren't the same. They operate on a single ground with 2 switched power sources.
Excellent... that is a good thing to know.
Stephen (manta z) wrote:As much as I don't want to offend anyone, this is how people eff things up. They don't understand the things they are messing with and could cause some major issues. If you have a Haynes manual you could have easily went into the wiring diagram and seen this as well(giving the fact you know what your looking at, in this case maybe you shouldn't be messing with the wiring till you learn on reading wiring schematics.)
This isn't directed to you, just a general statement that people need to understand that I'm hoping will come up in searches etc(Topic having "how are" should be common enough lol)
I actually do have a haynes manual, 2 of the actually... But one only goes to 2000, the other only goes to 2001... but oddly... the only wirting diagrams for headlights and such are for "95" and "96 up" and there is nothing at all for "00 up" which we all know are totally different. So the haynes manual failed me, and this is why i came here...
I also wonder how exactly the DRL's and bulb indicators work.... Do the DRL's on an 02 use the low beam or high beam filament? obviously it must just use the same wiring, but i assume uses some sort of resistance in the "switched ground" to control the brightness? And then what does the car monitor that lets it know if a bulb is missing or burnt out? (what trips the service light) I was doing some tinkering with LED turn signals, and i noticed that the LED's causes the turn signal to do its high speed blinking like a strobe light, like you get if a bulb is burnt out or missing... So i imagine this must be due to the different resistance of the LED's opposed to the filament bulbs. Is there a way to "trick it" into thinking it has the proper resistance? I know you can add a resistor to add resistance... but how can you LOWER resistance, without robbing power from the LED's
and i totally agree on the whole "dont just stat messing with things till you know" bit... as you notice which is why i did "tests" and consulted my haynes, and researched on here before doing anything major.
