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HEADLIGHTS ONLY TURN ON WHEN "CRANKING"

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Hi Guys,

1975 BMW 2002 manual

I've been using the search function on this issue for the last week, but havent found anything related to it.

I have a feeling my wires connected to my ignition switch arent connected correct. However, after searching and finding great wire diagrams on here, I believe some of my wires on my ignition switch have been replaced (ie, I dont see a black single wire, and a couple other wires that dont see to be helping my issue).

So the run down:

I'll get in my car, pull the parking and headlight switch. Parking lights come on perfect, no issue there....but the headlights dont turn on.

I'll put the key in and turn it, still no headlights...

only when i turn the key all the way to crank the starter, thats when the headlights turn on..but as soon as i turn that key back, the headlights go off.

So i've cancelled out any relay/fuse problems because the headlights obviously work nice and bright, and

*the headlights worked great before i started messing around with the ignition switch wiring*

(thats another topic for a different day)

Thanks to anyone that chimes in!

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That's incredibly weird, I would probably disconnect the started check for voltage on the plug for the headlights and have someone "crank" the car while I'm checking for voltage and try to trace the wire all the way to the source of the problem. But yeah pretty weird!

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it definitely sounds like you have the wires switched around, there are two green wires, it sounds like one of them is going to the correct terminal and the other is not, if the wire colors are wrong then you need to get out a test light and do some testing.

on the switch:

terminal 30 should be power in, two sets of wires (red)

terminal 15 should be switched power out (green)

terminal 50 should be starter (black)

terminal R should be accessory (purple)

terminal P should be the one that goes to your low beans and turn signals (single green wire)

it sounds like the wire that should go to terminal P is somehow spliced to terminal 50 if your starter and lights both work at the same time. If the starter doesn't work then we know what the problem is, you have somehow lost the starter wire and plugged the single green wire into the terminal 50.

look here:

http://www.bmw2002faq.com/component/option,com_forum/Itemid,57/page,viewtopic/t,369913/start,0/postdays,0/postorder,asc/highlight,ignition%2Bswitch%2Bdiagram/

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terminal 30 should be power in, two sets of wires (red)

terminal 15 should be switched power out (green)

terminal 50 should be starter (black)

terminal R should be accessory (purple)

terminal P should be the one that goes to your low beans and turn signals (single green wire)

I get so close to this, but there are a few hiccups:

-i dont see a single black wire for terminal 50. I do see a thick black wire, BUT its also paired up with a thick red wire connect to the same spade. is this correct?

-for terminal 15, is this two green wires (one thick, one thin) paired up into the one spade?

I guess i could do the reverse approach and tell you guys what wires i do have under there:

-Thick red wire 1

-Thick red wire 2

-Purple wire

-Light green wire with black stripe running down it

-Solid black wire paired up with red wire into same spade

-Two green wires (one thick one thin) paired up into same spade

Thanks in advance for all your help. I've been working on cars for the last ten years, but I HATE electrical issues!

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terminal 30 should be power in, two sets of wires (red)

terminal 15 should be switched power out (green)

terminal 50 should be starter (black)

terminal R should be accessory (purple)

terminal P should be the one that goes to your low beans and turn signals (single green wire)

I get so close to this, but there are a few hiccups:

-i dont see a single black wire for terminal 50. I do see a thick black wire, BUT its also paired up with a thick red wire connect to the same spade. is this correct?

-for terminal 15, is this two green wires (one thick, one thin) paired up into the one spade?

I guess i could do the reverse approach and tell you guys what wires i do have under there:

-THICK RED WIRE

-THICK RED WIRE

-PURPLE WIRE

-light green wire with black stripe running down it

-solid black wire paired up with red wire into same spade

-two green wires (one thick one thin) paired up into same spade

Thanks in advance for all your help. I've been working on cars for the last ten years, but I HATE electrical issues!

If you look at the little diagram in the link I posted you can just match up the colors and you will be fine, it doesn't matter which green wire goes to which green terminal, same with the red. The oddball is the black and red spliced wires, that is not original to the best of my knowledge and may be your problem, try tracing where the red wire goes, is is separate from the bundle of original wires?

It may be that an alarm starter kill relay was installed at some point and that wire was fiddled with. If it were original red would indicate unswitched power so it would not be attached directly to a black wire that usually indicates signal or momentary switched power.

I would plug everything in but your starter wire and then turn the key to start and see if the headlights come on, it could be that you have a bad switch and we are barking up the wrong tree. If the lights come on then I would suspect the switch since nothing is connected to the terminal that supposed to control that.

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Thanks for the great input. I will try this as soon as I leave the office.

If nothing improves, I will take some photos tonight and post them up for a more clarified approach.

Thanks again everyone.

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Alright,

Well I made some progress last night. The black wire I thought was the starter turned out to be the headlight (weird)

Anyway, all the lights work perfectly now. However, I cant get the damn car to fire now. It will crank all day, but just wont start.

Pardon my ignorance, but does the wiring connected to the ignition switch somehow effect if the car will fire up or not? This is my first 2002 (honda guy before this), and the car appears to have an upgraded distributor.

Is it possible that I mixed around the plugs and now the system that sparks the car is not getting any voltage?

I bought a meter yesterday at lunch, so I'm ready to tackle some troubleshooting...just dont know where to start on this car.

Thanks, guys.

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having just gone thru ignition issues, i'd suggest checking to insure that you have power at the + coil when the key is turned on and the wire's still connected to the condenser

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1. Headlights on all squarelight (land later roundie) 2002s only function with the ign on. Therefore the headlight wiring goes through the ign switch. Parking and tail lights work with the ign off, so they're functioning as they should. So...the headlight wire at the ign switch should be connected to the ign switch terminal that's live when the ign is turned to the run position.

2. Same with the coil. It's energized only when the ign is on, so it should be connected to the ign switch terminal that's energized when the key is turned to the "run" position.

Usually on 2002 ign switches, the big red wire is live all the time--it powers everything that runs through the ign switch...find it with a voltmeter and make sure it's attached to the proper terminal on the switch. Then locate the wire at the switch that runs to the coil. Use a test bulb or voltmeter connected to the coil input terminal to find it. That wire, along with the wire that feeds the headlights, should be on the ign switch terminal that goes live when you move the key to the run position, and they should remain live when you turn the key to start.

cheers

mike

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I think I disagree with Mike's last statement ("the headlights . . should remain live when you turn the key to start"), at least on our '75 and '76.

In both cars, with the headlights on, when the key is turned to start it kills the headlights. I assume, so as to eliminate that addition drain on the battery.

Bob Napier

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hibernation--think the headlights stay on when the key is in the start position but I'm not sure. I do know the earlier cars don't have the headlghts wired through the ignition, as my '69's headlights stay on even after I take the key out of the ignition...I learned that the hard way many years ago and ran the battery down.

mike

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