Headlights
Printed From: the12volt.com
Forum Name: Lights, Neon, LEDs, HIDs
Forum Discription: Under Car Lighting, Strobe Lights, Fog Lights, Headlights, HIDs, DRL, Tail Lights, Brake Lights, Dashboard Lights, WigWag, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=42914
Printed Date: May 21, 2024 at 8:17 PM
Topic: Headlights
Posted By: bmw5002
Subject: Headlights
Date Posted: November 13, 2004 at 8:52 PM
Look at the highlighted part in the following wiring diagram.  It would appear to me as if the R/G wire is grounded and the lo-beams are on. When i switch the hi-beams on, the R/Y wire would become grounded and the R/G wire open, therefore letting current flow to the highbeam indicator and turning my hi-beams on. The part where I get confused is, when the hi-beams are on, are both filaments in the bulb on, or does it switch like lo-beam filament, and hi-beam filament? If so, does that mean I could energize BOTH filaments at the same time, to get the output of my hi-beam + my lo-beam? Is this normally how car headlights work? Please enlighten me. Do you think it would have any effect of the headlights if the hi-beam indicator light was burnt out? Thanks
Replies:
Posted By: Mad Scientists
Date Posted: November 14, 2004 at 6:03 AM
bmw5002 wrote:
It would appear to me as if the R/G wire is grounded and the lo-beams are on. When i switch the hi-beams on, the R/Y wire would become grounded and the R/G wire open, therefore letting current flow to the highbeam indicator and turning my hi-beams on.
Yes, the multifunction switch supplies a ground for the headlights.. Yes, with the high beams selected you should see 12v on R/G. Yes, the high beam indicator is supplied off the low beam ground wire R/G. bmw5002 wrote:
The part where I get confused is, when the hi-beams are on, are both filaments in the bulb on, or does it switch like lo-beam filament, and hi-beam filament? If so, does that mean I could energize BOTH filaments at the same time, to get the output of my hi-beam + my lo-beam? Is this normally how car headlights work? Please enlighten me. Do you think it would have any effect of the headlights if the hi-beam indicator light was burnt out?
Normally either the high beam OR low beams are on.. not both at once. They can be wired to do so, but watch for excessive heat generated. Is the high beam indicator bulb burned out.. or just not lighting up. A wiring problem (specifically an open in R/G upstream of where the high beam indicator ties in.. along with other possibilities)
Jim
Posted By: bmw5002
Date Posted: November 14, 2004 at 1:03 PM
The indicator doesn't light up, i am assuming it is a wiring problem because i remember checking the instrument panel bulbs when i had to swap out the speedo. There is a rather major wiring problem. I have a break somewhere along the harness for my lo-beams. So only my hi-beams work. I don't wan't to try to find the break because it would seem like it might be hard to find a break in a wire that is all bundled up with a bunch of other wires and snaked all around the car. So to fix this problem I am patching directly into the harness coming out of my multifunction switch and wiring up two 30A relays with 10guage wire and putting in new 80/100W bulbs instead of the 45/65W that are in there now. So im basically rewiring my headlights. I hope I don't melt the headlight from the new bulbs :-/
Posted By: Mad Scientists
Date Posted: November 15, 2004 at 5:48 AM
It sounds like there is an open in the R/G wire.. somewhere between the splice connecting both headlights together and the connection for the high beam indicator. Personally, I'd spend some time trying to find the break.. maybe it's easier to just rewire the headlights, but the practice would do you good. There may come a day where you _have_ to fix the wiring.. having done it before would help on that day. I'd start probing the R/G wire at the headlights looking for where I lost 12v. Try first at the center of the harness in the engine compartment and you've cut the area to be search in half. (Obviously with the headlights on). If you just can't find the break.. just run a new R/G wire from the headlights to the multifunction switch. Jim
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