Source of switched power (accessories) for stereo install

[cvvick]

I'm installing a headless  amplifier/radio/Bluetooth unit in my 1974 2002tii. Where (under the dash) would be a good place to tap for switched power.  Barring that, what about just power?

[BMW 1600-2]

There is a switched line for radio taped off behind the center console on the wire bundle going to the emergency flasher switch.  It is purple with a white stripe and goes back to fuse #6.

[BMW 1600-2]

For unswitched power, the cigarette lighter or the power to the tii clock are good places.  For the clock, the location is very convenient provided that the current is small (e.g. for keeping presets).  I have an E12 radio that requires switched and unswitched power.  For the unswitched power with a very low current requirement, I made a plug-in pigtail to the clock so I wouldn't cut or tap any wires.

 

The best ground in the are is the left attachment point  for the heater box.

[jimk]

2 hours ago, BMW 1600-2 said:

For unswitched power, the cigarette lighter or the power to the tii clock are good places.

Doesn't the power for the clock pass thru the dash printed circuit board?  I may not carry any amount of amperage.  I wouldn't want to burn the trace in the board.

 

The constant power wire to the board could be tapped.

Edited November 5, 2023 by jimk

[conkitchen]

I smell smoke 

[BMW 1600-2]

If you’re nervous about using the power to the clock, then use the cigarette lighter.  In either case you can make a pigtail that plugs in rather than splicing a wire.  In the case of my radio, all the unswitched power is doing is maintaining preset radio stations and the draw is only a few milliamps so I’m not worried about burning anything in the instrument panel.

[jimk]

1 hour ago, BMW 1600-2 said:

so I’m not worried about burning anything in the instrument panel.

Have at it then.

[John76]

There should be a female connector on the hazard wiring harness.

 

[Conserv]

9 hours ago, John76 said:

There should be a female connector on the hazard wiring harness.

 

Wait, John! Your ‘76 grew a second horn? 😯😋 I won’t resort (yet) to the low-humor that might engender… 🙄

 

So… when BMW saved millions — i.e., made millions — by switching to a single horn, which horn did they use: 335 or 400 Hz? I’m guessing you backfilled your car with the missing one. Or is it more complicated than that, e.g., BMW split the difference and provided a single 367.5 Hz horn? 
 

Thanks and best regards,

 

Steve

 

 

[Son of Marty]

The idea behind the high and low horns different frequency's is that the off tone honk draws more attention than a harmonious sound would. 

[cvvick]

23 hours ago, BMW 1600-2 said:

There is a switched line for radio taped off behind the center console on the wire bundle going to the emergency flasher switch.  It is purple with a white stripe and goes back to fuse #6.

Here's what mine looks like. I do see or feel the connector following the wiring harness. Notice that one my violet white wires have been cut. Is that an option?  It done appear to have power. Does the hazard switch need to be connected?

[BMW 1600-2]

Looks like someone cut off the connector.  Here's what it looks like from the factory on my car, but with the tape pulled off...

[John76]

9 hours ago, cvvick said:

Does the hazard switch need to be connected?

No ... the Violet/white wire is a switched 12V source directly from the #6 fuse, even if the hazard switch is not plugged into the connector.

The hazard switch is also powered with a Red/white wire that is 12V (always hot) from the #2 fuse.

Use the fuse-protected Violet/white wire (switched 12V) for your radio.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[Stevenc22]

15 hours ago, cvvick said:

Here's what mine looks like. I do see or feel the connector following the wiring harness. Notice that one my violet white wires have been cut. Is that an option?  It done appear to have power. Does the hazard switch need to be connected?

 

That's the correct wire there. Just crimp on a new connector and use it.

[Henning]

12 hours ago, BMW 1600-2 said:

Looks like someone cut off the connector.  Here's what it looks like from the factory on my car, but with the tape pulled off...

Note that this wire is cold on "Stop", hot on "O" and "Fahrt" and cold on "Start". I'm not so happy with this since the stereo has to refind the radio station or the current track from the usb stick. And oh yes, my car does love hardrock.

 

henn