Low Beam Issue

[jag09]

I picked up a 1990 325i coupe a week or so ago knowing it had some issues. Such as the Power Steering being blocked off, but not the proper way, along with not knowing when the timing belt had been last replaced. Onto the headlight issue. When I pull out the light knob to the first notch the low beams will not activate. When I pull the knob out all of the way, and flip on the high beams the low beams will then come one. I checked fuses to see if any were blown and they all checked out good. Today I bought headlights just incase the low beams were blown. Any idea on what could be causing this?

[roguetoaster]

When you pull the switch to position one the low beams will not activate, however, the parking lights (+city lights if a ROW model) will activate. Low beams should activate on position two.

[jag09]

When I put the knob in the second position the Low Beams still do not come on. They will only come one when I turn on my High Beams. Could this be a wiring issue? I have very little information from the PO, so I am just trying to get a general idea as to what it could be before I send it to a shop or something

[StereoInstaller1]

Im guessing the car has sealed beam headlights?

[jag09]

Im guessing the car has sealed beam headlights?

Yes it is.

[LateFan]

As I understand it, the lows run off fuses 13 and 14. When you flip to brights, those are powered through fuses 1 & 2. There is a high beam relay on the panel as well.

But it sounds like it might be in the switch.

[StereoInstaller1]

So, the first step is to grab a testlight, turn on the low beams and test fuses 13 and 14. Don't even bother looking at them, test for power, since they get power after the switch.

If they have power, next step is to test for power at the bulb itself. If there is power, test for ground by clipping the test light to the positive and probing the brown. If you have power and ground, the bulb is bad...and all this becomes a stupid but funny thread.

If they dont have power, first thing to do is check the relays for the correct part number, then drop your underdash panel and test for power at the switch.

Obviously if the relays are wrong (just because it fits doesnt mean it works) fix that first, then proceed.

All of the wiring info can be found in the ETM, its easy enough to find.

HTH, GL.

Luke

[Das Delfin]

Aside from the troubleshooting Luke posted, which is the correct way to diagnose electrical stuff.. sealed beam low beams have both a high and low beam filament inside, and when you flip on your high beams, only the high beam filament lights up. Which implies that something on your low beam circuit doesn't work.

I would check your low beam relay (I think K4.. it's been a while) and make sure it works/is the correct one. Also check the two low beam fuses while you're at it. If both these look okay, check your low beams lights themselves with a meter by finding continuity across ground and each of the hot prongs.

If that quick check using deductive reasoning doesn't work, then get a meter and check your switches, etc, and good luck