Miscl. Electrical 

Electrical schematics for Hazard flasher system, fold-out fog/driving lights & heated grips.
            VDO instruments. Replacing a /6 left-side bars switch.  Substitute voltmeters and clocks.     ETC.  
© copyright, 2011, R. Fleischer
38-B
misclelectrical.htm

(1) The Hazard warning lights system, standard:

This schematic diagram is from the Factory Service Manual, for 1983, and is a large .GIF format.  It has my messy notes on it.  It is typical of the Hazard lamps function circuitry.  Rotate 90°, and then print or print, and view the long side to right-left. With respect to the rotated image:...the item in the upper left corner is the normal flasher unit, the wire leading upward goes to the turn signal switch on the handlebars.  This normal flasher unit is used for the hazard function and normal function, on the airheads. 

The function of the circuit is complicated:  When the ignition switch is turned on, Relay (8) at the lower right is then energized, & power flows through that relay to both the flasher terminal 49, and to terminal 30 on the hazard switch, item (7).  When the hazard switch is turned ON, power comes from terminal 49d of that switch, keeping relay (8) powered on, even if the ignition switch is then turned off (until the hazard switch is turned off).   The purpose of diode (4) is to prevent the circuitry from back-feeding the rest of the motorcycle (keep THAT in mind, if that diode shorts!!).    When the hazard switch is turned ON, the hazard switch, via the R and L terminals, puts all the turn lamps in parallel...so all are energized.    The turn signal switch and individual lamps, and wiring to the flasher is not shown on this schematic, but it is standard.

(2)  Schematic diagram (Factory Service Manual) for the optional fold-out lamps for the RT fairing, called 'Additional Driving Lights':
    It consists of a fog light and a driving light, and associated parts.  This is a reasonable sized .gif format, of 576 x 630 pixels, and can be downloaded into your imaging program, and you can use the zoom feature, and all necessary small fine details will show up quite well. 
I have TWO styles of these diagrams on this page, see further below for the Euro, or RT style.

Nebelscheinwerfer is the fog light; Zusatzfernscheinwerfer is the driving light.   
As with all BMW wiring sketches:
BR = braun, brown, common chassis ground
RT = rot, red
GE = gelb, yellow
GN = grün, green
WS = weib, white
BL = blau, blue
GR = grau, gray
SW = schwarz, black
VI = violett, violet
TR = transparent, transparent

NOTE!   For those installing extra lamps, or have specific reasons to replace an existing flasher unit,....ETC.....there is a heavy duty flasher unit available at auto-parts stores, under the Signal Stat brand, model 263.   Mechanical and electrical.  Flash rate is 60 to 120 per minute, has 3 each 1/4" male spades, is 1.33" round, 1.35" high, works on 11-15 volts, and from well below freezing to damned hot.  It will handle 20 ampere loads!!

Here is the EURO RT style of these flip-out-lights; original pdf was courtesy of Doug Dokken, dcdok@comcast.net; which I have converted to a jpeg here:

(3)  VDO instruments:   It is possible to substitute VDO instruments, such as:
    Voltmeter:  #332-103.   This fits the original 2-1/16" round hole, is well-dampened, and has WHITE LETTERING.  It uses a spin-on clamp.  Has through-dial lighting; and using diffusers, can have red, green, or white lighting.  It has a 8 to 16 volt scale, just like the original one in your Airhead. 

    Clock:        #370-152
Those are black face and black bezels, and have a threaded part to mount them, rather than a bracket.
That was discontinued, and the new number is 370-100B.   These are way too pricey for most to consider.

You can also use VDO Vision Marine voltmeters and clocks.


(4)  Substituting an accurate DIGITAL meter for the existing BMW in-dash round meter...or, just adding one:

There are digital voltmeters on the market that require a separate power source. There can be problems with them! Some of these require...or MAY require
 a separate, perhaps 9 volt, supply.  The worst part is that often that supply negative is NOT common to the measuring side of the meter....UGGGH!       These are very difficult to use, and some use them with an external small 9 volt battery.   I recommend you do NOT use this type; there is NO NEED TO.  The type of digital meter I recommend you install in your bike (airhead, K bike, ETC.) is a TWO WIRE METER.  These meters provide their own power from what they are measuring.  They need NO lamp either!  They are LOW DRAIN.   These meters are available in LED and LCD versions.  The LED version is much more visible in all conditions of lighting (day, night, etc.), and pulls only a faint bit more current ...and that is totally negligible on your bike, if you wire it so the meter is powered AFTER the ignition switch.  Drain is UNDER 0.020 ampere! for the Datel (Murata) unit...that is under 0.28 watt!  It is BRIGHT!!
There are numerous types of digital meters available.  
        a. To install a ROUND faced digital voltmeter in the Airheads, in place of the existing round voltmeter, I use a 2-1/16" round faced type from such as
             Summit Racing, in this country.   See also www.lascarelectronics.com, they have BOTH round AND rectangular digital meters.
        b. To install a rectangular type digital voltmeter:  My favorite meters came from  www.datel.com    This is now http://www.murata-ps.com/
            Good quality, rugged, reliable, accurate, red or green or blue digits, and work fine at any temperature. I recommend RED digits.
             See also www.bikemeters.com or   www.digitalmeter.com   (Retail outlets primarily, Datel type meters, with information, so snoop around).
             I recommend Datel's (murata-ps.com) model number DMS-20PC-1-DCM-C.  These draw only about 13 ma when powered.     If you want a
             panel bezel, the part is DMS-BZL4-C, with gasket.   The meter will read accurately from +8 to +50 volts D.C.
            These are two wire, self-powered, need NO LAMPS.  They are encapsulated, in a polycarbonate case, and are VERY rugged.  RED digits
             for the above number.  If you want blue digits the number is DMS-20PC-1-DCM-B-C; and for green digits it is DMS-20-PC-1-DCM-G-C.
            The LED's are 0.37" high.  Do NOT purchase the 0.01 volt resolution type (has an extra digit), as it is WAY overkill, and the always
             changing indication on the right-most digit will drive you crazy.  You need only 0.1 volt resolution, even for critical work on your bike;
             and the only such work is in setting the voltage regulator for the alternator; or using the meter with leads attached as a test instrument
             for setting the Voltage Regulator or measuring circuit drops.
             Some manufacturers will call this type of meter a 3-1/2 digit type.  That basically means that at 10 volts and higher, it
             simply adds a digit 1.   Heed this advice....do NOT get the 0.01 volt resolution meters.
        

Anecdote:  Back around 1999 or so, I designed a special 2-1/16" round faced digital voltmeter, and had a company run off a batch of them.  The Company was originally called Intellitronix (C.R. Industries) and became Nordskog, in the USA.    May still be at www.nordskogperformance.com.
I sold all of them except one, to Airheads.  One production version was put on my own bike, and I put my personal prototype on another of my Airheads. A
few years later, I wanted a much larger batch made, and the company refused. I could not find another company to make them inexpensively, so dropped the
project.  Later, I found that nearly the identical meter was being sold by them to various hot-rod shops, such as Summit Racing, who resold them to the public.  These plastic-cased meters are actually pretty darn good.  Various types are available, some with push-buttons on the face to enable storing peak voltages, ETC.

5.  Schematic diagram for the heated grips.
     In this diagram:  Item 1 is the battery
                              Item 2 is the ignition switch
                              Item 3 is the kill switch
                              Item 4 is part of the fuses area
                              Item 5 is the connection for optional extras
                              Item 6 is the heated grips electrical connection
                              Item 7 is the heated grips switch
                              Item 8 is the LEFT grip heater element
                              Item 9 is the RIGHT grip heater element

For a .pdf schematic click here:  airheadheatedgrips

6.  Replacing a /6 left-side bars switch:
If you try to order a new lights switch (the switch assembly on the left-side of the handlebars) of a /6, you will likely be sold a /7 assembly.  You will be confused.  The original had 9 wires, the new one has 8 wires.  How do you wire the new switch?
a.  Disregard the RED wire.  It was part of the /6 switch because on the /6 you could flash the high beam withOUT the ignition switch being on.  That disappeared with the /7 switch.
b.  The green/black wire of the new switch needs to be connected to the brown section of the contact plate.    This takes the place of the old brown wire.  It is the horn wire.  The reason for this brown wire becoming a green/black is that in the /6, it sends a switched ground to the horn, but in the /7, it uses a switched HOT for the horn.


Revisions:

11-14-2005:  add (2)
12-24-2005:  Add (3)
03/12/2006:  Add (4)
05/17/2007:   Remove original poor scan of Hazard circuit and replace with high resolution scan
09/25/2007:  Modify both images, both are now .gif, and are detailed enough for good usability
                        if downloaded to an image program and zoom feature used.
08/22/2008:  Remove PowerBoxer.de hyperlink, it is dead
07/24/2009:  Make a new Hazard lights scan at higher resolution and size and change gamma, renumber items.
11/22/2009:  Make upper image smaller.  Remove partial artifact from lower image.
12/05/2009:  add Signal Stat information
02/01/2010:  add information to (3); and new section (4)
02/06/2010:  Add heated grips schematic
03/02/2010:  fix hyperlinks
04/09/2010:  Update item #4 to agree with latest Murata website numbers, and clarify the information for readers.
04/22/2010:  Add pdf link for euro version of flip out lights
07/20/2010:  Problems with that PDF, so made into jpg, and inserted into this page.
04/30/2011:  Add #6
09/09/2011:  edit #3
12/24/2011:  Add note regarding aftermarket grips

© Copyright, 2011, R. Fleischer

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