Rear Brake Light - Where does the power come from???

[cxzsaq]

All,

As some of you may know, i cant get the brake and reverse lights to work on my 72tii clone.

I think I may not have any power going to the brake light because my hazard lights (turn lights) work when i hit the hazard button.

My turn signals don't work however when i engage turn left or right on the stalk.

My windshield wiper motor also does not work.

so...for the brake only question: looking at the pic below, i have 2 wires on the top of the brake bracket - one going to the back and one supposedly coming from the fuze box. question: which fuze # should it connect to? Most diagrams point to 12.

Is there a way to test if I'm even getting power to fuze 12 or better yet, to that purple wire leading to the brake light switch? Should it be around 12v with the ignition set to "ac"? If its getting power and the brakes don't work (brake light switch works) then the issue is the wire leading to the brake light. Thanks all.

[c.d.iesel]

test / clean / replace all the fuses

[Napes]

You will notice in c.d.'s post that the tail lights are on seperate fuses, so that if one fuse blows you will still have the other tail light. Also note that the brake switch in your photo is adjustable from front to rear with the two nuts on each side of the mounting bracket. Possibly moving it forward or aft (I forget which direction would enhance the contact, but I think aft would do it) may solve the problem. That's what SOs, or friends are for - stand behind the car and let you know what's happening as you adjust the switch.

Bob Napier

[cxzsaq]

test / clean / replace all the fuses

when i test the wire coming from the fuze - the violet wire - should it be the same voltage as the battery?

[cxzsaq]

You will notice in c.d.'s post that the tail lights are on seperate fuses, so that if one fuse blows you will still have the other tail light. Also note that the brake switch in your photo is adjustable from front to rear with the two nuts on each side of the mounting bracket. Possibly moving it forward or aft (I forget which direction would enhance the contact, but I think aft would do it) may solve the problem. That's what SOs, or friends are for - stand behind the car and let you know what's happening as you adjust the switch.

Bob Napier

Bob. Thank you. The issue is not with the switch - it activates right after i press on the brake pedal - i conducted a connectivity test.

Also, why doesn't cd's schematic match bmw's own diagrams - the same diagrams that are supposed to match these stickers.

http://www.2002tii.org/diagrams/bmw2002tii-usa-mod71.pdf

[bnam]

I think his posting was for a later car 73 or 74(?)- on. Perhaps your's is an earlier version?

[cxzsaq]

I think his posting was for a later car 73 or 74(?)- on. Perhaps your's is an earlier version?

Yes. Mine is a 72tii.

[Napes]

You might be able to find the wiring diagram info you need here:

2002tii.org

Bob Napier

[cxzsaq]

You might be able to find the wiring diagram info you need here:

2002tii.org

Bob Napier

Already did.

http://www.2002tii.org/diagrams/bmw2002tii-usa-mod71.pdf

All i want to know if that wire (violet) should be getting power and how much - I can figure out the drawings myself.

[Mike Self]

I think I may not have any power going to the brake light because my hazard lights (turn lights) work when i hit the hazard button.

* On a '72, the 4 way flasher is fuse 8; brake lights are fuse 12, so you have two problems.

My turn signals don't work however when i engage turn left or right on the stalk.

* This sounds like a problem with the switch (stalk) rather than the flasher unit or the fuses as the same flasher relay is used for the 4 ways as well as the turn signals, and left and right T/S bulbs are on separate fuses (5 for left, 6 for right)

My windshield wiper motor also does not work.

* wipers are on fuse 12, as is your horn and backup lights. If all are inop, there's a problem either with the fuse or the fusebox.

so...for the brake only question: looking at the pic below, i have 2 wires on the top of the brake bracket - one going to the back and one supposedly coming from the fuze box. question: which fuze # should it connect to? Most diagrams point to 12. **12 is correct.

Is there a way to test if I'm even getting power to fuze 12 or better yet, to that purple wire leading to the brake light switch? Should it be around 12v with the ignition set to "ac"? If its getting power and the brakes don't work (brake light switch works) then the issue is the wire leading to the brake light.

* with the ign on, the wire coming from the fuse box to the brake light switch should be hot. The brake light switch is a "normally on" switch--when the button is out, the switch passes current. Easy test--with the two wires connected, short across the two switch terminals. If the brake lights work, it's the switch. Sometimes you can get an inop switch to work by having someone hold the brake pedal down, and then snapping the switch button several times andor squirting with a little WD40.

cheers

mike

[cxzsaq]

I think I may not have any power going to the brake light because my hazard lights (turn lights) work when i hit the hazard button.

* On a '72, the 4 way flasher is fuse 8; brake lights are fuse 12, so you have two problems.

My turn signals don't work however when i engage turn left or right on the stalk.

* This sounds like a problem with the switch (stalk) rather than the flasher unit or the fuses as the same flasher relay is used for the 4 ways as well as the turn signals, and left and right T/S bulbs are on separate fuses (5 for left, 6 for right)

My windshield wiper motor also does not work.

* wipers are on fuse 12, as is your horn and backup lights. If all are inop, there's a problem either with the fuse or the fusebox.

so...for the brake only question: looking at the pic below, i have 2 wires on the top of the brake bracket - one going to the back and one supposedly coming from the fuze box. question: which fuze # should it connect to? Most diagrams point to 12. **12 is correct.

Is there a way to test if I'm even getting power to fuze 12 or better yet, to that purple wire leading to the brake light switch? Should it be around 12v with the ignition set to "ac"? If its getting power and the brakes don't work (brake light switch works) then the issue is the wire leading to the brake light.

* with the ign on, the wire coming from the fuse box to the brake light switch should be hot. The brake light switch is a "normally on" switch--when the button is out, the switch passes current. Easy test--with the two wires connected, short across the two switch terminals. If the brake lights work, it's the switch. Sometimes you can get an inop switch to work by having someone hold the brake pedal down, and then snapping the switch button several times andor squirting with a little WD40.

cheers

mike

Mike.

Thank you.

This is what I was looking for. The brake switch works ok - so I will check the "hot" wire for voltage when the car is running (i hope next week). I will hook the wire up to fuze 12 and see what happens. I assume it should be getting 12v or whatever the battery is reading?

Mike, do you know by any chance if all other fuzes should be reading 12v?

[cxzsaq]

fyi - updated diagram snippet of what i think needs to be connected to 12 - based on the key provided with diagram.