Mystery bulb and wires behind console/dash

[Marsattacks]

I have (1) searched the FAQ; (2) studied the wiring diagram; and (3) looked through the articles in the technical section.  No luck so far.  Here is my question:

 

I am attempting to hook up an IR repeater so I can control my hidden stereo with the remote.  It ideally needs switched power.  I found a taped off set of wires behind the console.  There is:

 

(a) A yellow/white wire that goes to a small bulb.  It says SPAHN 12v2.  It does not appear to work so probably is burned out.

(b) A red wire.  This wire shows 12v with the key on or off when the brown is grounded.  This is a female spade.

(c) A brown ground wire.  This is a male spade.

 

Photo below.

 

I am not sure how switched and un-switched (always on) wires work.  I assume the red is unstitched due to the constant power.

 

The yellow also seems to get power with the key on or off, which seems odd to me.  Doesn’t seem like it should do that unless there is something funky about the way a separate switch would interrupt ground until it is pressed.  I guess like the horn.  Please realize that I don’t know what I’m talking about so if this seems like nonsense it probably is.

 

Now for the question — does the FAQ hive-mind know what this might be?  And do you see any major problem with running the IR repeater from it?  Seems like there would be a tiny draw.

 

If that is a bad idea is there a nearby switched power that you recommend?  I’ve read a little about taking power from the hazard switch — which is sitting right there — but I am slightly nervous about that.

 

Thanks. — John

[02Les]

May have been a clock (tii type) at some time.

[Marsattacks]

Dang!  I think you are right! My car is a tii and Zenwrench Paul very nicely hooked me up with a motometer clock.  It was wired but didn’t work. My brother in law disconnected it when we put on a dash cap.  The cap is now removed and I forgot about that phantom harness.  I actually never knew it had a light!   I think it should work fine for the IR repeater.  

[Mike Self]

Do you need switched power for your repeater (only hot with the ignition on) or should it be live all the time?  

 

You can source both from the back side of the ignition switch as well as the emergency flasher switch.  That switch has two sets of switch points inside:  one to power the emergency flashers (always hot) and one to provide power to the turn signals (hot only with the ign on).  Use a voltmeter to determine which is which.  

 

mike

[John76]

3 hours ago, Marsattacks said:

 I actually never knew it had a light!

This is the clock dial illumination bulb. Check the light by turning the headlights "on" and twisting the knob to increase or decrease the brightness.

The hazard button has a violet/white pigtail with a female connector. This provides fused 12v  for the radio (key turned to  #1 and #2  position). The red/white wire on the hazard button is a fused 12v source, always hot.

The solid red wires are always hot. The solid green wires are switched hot. Neither solid wire is fuse protected!

A fused red/white wire with a female connector can also be found under the steering wheel (near the horn contact ring). This is always hot, and was used for the ignition key buzzer, which most owners removed and tossed in the trash (very annoying!) 

Any green/white wire you find under the dash is a fused 12v source that is only hot when the ignition is on (key in #2 and #3 positions). 

Rule-of-thumb with BMW wires: Solid color wires are not protected by a fuse. Striped (power) wires are (generally) fuse protected.

 

[Marsattacks]

Thanks guys. Super helpful.  Will report after I scope it out.  

[Marsattacks]

Thanks all — resolved!  The violet striped wire from the hazard switch was covered with some tape but had a fresh bayonet connector so I crimped on onto my IR repeater and found some good ground under the console.  Works a charm and the radio is totally hidden.  Also runs Sirius/pandora/Spotify/cell phone.  Really a nice addition.  Next up—docking station fitted into the dash seatbelt binnacle.