From digest.v7.n855 Wed Dec 31 13:38:49 1997
From: Jim Cash <j.cash_at_sympatico.ca>
Date: Wed, 31 Dec 1997 12:41:35 -0500
Subject: MOD for Side Turn Indicators (E28 & some others)
E28 MOD - Rewire Side Marker Lights as "Auxiliary Turn Indicators"
A few weeks back there was some dialogue on the digest about adding the
"Auxiliary Side Turn Indicators" to some cars that did not have them.
The additional indicator can be a helpful safety feature, especially on
those E28ís with the North American style bumpers where the parking/turn
signal could not be seen from the side.
Many of you already have these, and on many others the front "side
marker light" flashes, with the turn indicator, to provide the same
The early E28ís, and other models of that era, did not have that
feature. On those, the side marker light simply lights with the parking
If anyone wants to have them also "flash", with the turn indicators, the
following mod will do the trick.
MOD FUNCTIONAL DESCRIPTION
Description is based on 82 528e model. Others are similar, but there may
This mod re-routes the "ground" connection for the front side marker
lights. It disconnects it from the body ground, and connects it in
parallel with the hot side of the front turn indicator bulb.
Function - with parking lights "on".
This still allows it to operate as a marker light, but it now gets itís
ground "through" the turn signal bulb, which does not light since it is
a 21 watt bulb and the marker bulb is only 5 watt.
But - when the turn signals flash "on", this removes the ground for the
side marker lamp, and they flash "off" - thus the two bulbs both flash,
but in opposite phase.
Function - with parking lights "off".
In this case the side marker will flash "in phase" with the directional
The flashing circuit applies "battery" on the side of the marker lamp
that used to be the ground. Therefore it needs a ground on the other
side, which is the hot wire for the parking light. Since the parking
light circuit is off, there is no battery there , but there is ground
available "through" the front & rear parking light bulbs. In this case
the parking light bulbs are of similar capacity as the marker light (5
watt), but since the front and rear parking lights are wired in
parallel, they are the electrical equivalent of a single 10 watt bulb,
and therefore provide adequate ground capacity for the 5 watt side
Note: this will not affect the operation of the rear light check
DEGREE OF DIFFICULTY:
This is a simple mod - DOD 3/10
Wire cutters, soldering gun/solder, electrical tape.
- The front side marker lights are grounded with brown wires. They are
connected, with many others, to a body ground connection on the inside
of each front fender. Trace the brown lead from each front marker lamp,
and cut it just at the body ground connection. Strip back the insulation
- You now need to locate the "hot" wires going to front turn signal
lamps, on each side of the car. They are accessible by cutting into the
plastic wire harness, inside the front fender on each side. To make
this as easy as possible, choose a spot close to where you cut the
ground wire from the marker light, so that it will reach.
The wires you require are:
- Left (drivers) side - blue/red
- Right side - blue/black
If your car is not an E28, you may want to verify the colours by looking
at the rear of each front turn signal lamp socket.
- Do not cut these wires but rather strip a short piece of insulation
off each. Connect the "cut" brown ground wire from each of the side
marker lamps. Solder, and insulate with electrical tape.
- marker lamps should still come on with parking lamps.
- marker lamps should flash as directional signals with parking lamps
on, or off (remember they will work in different phases)
- All OK ? - Tape up the incision you made in the wiring harness.
Datís it - Eh !
Happy Signalling in the New Year.
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London, Ontario, Canada
BMW CCA 102929
E39 97 540iA