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DRLs for an E36 with Front Fog Lights

DRL’S FOR AN E36 WITH FRONT FOG LIGHTS
(RON STYGAR’S INSTRUCTIONS REWIRED)


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I changed Ron’s wiring to make the Daytime Running Lights go off as soon as you switch on the parking lights. That way you can drive in really thick fog with just the front fog lights on – and the DRLs off, so that they don’t blind you. You can also briefly kill your headlights to thank someone at night and not blind them.

I connected pin 1 of the Canadian DRL module to the light switch pin 9: to kill the DRLs whenever the parking/position lights are on and follow the owner's manual. I spliced pin 1 of the relay to the 0.5 mm2 GE/VI [yellow/violet] wire running to light switch pin 9.

I connected pin 5 of the module, through a low-current on/off switch, to the 0.5 mm2 GN/GE [green/yellow] wire running to light switch pin 8. Tapping pin 8 will kill the DRLs as a fail-safe should fuse F22 open; otherwise, the DRLs will not go off.

The DRL Module (61 35 8 368 039) may be missing pin 7 which will disable the front fog light relay and lights of a U.S. market car. The easiest fix is to disconnect from pin 7, the thin, 0.35 mm2 RT/WS [red/white] wire and ground it. The fog lights will then stay on with the high beams, as in Europe.


A FEW MEASUREMENTS OF THE DRL RELAY

 Pin 2 (2.5 RT/WS) outputs a roughly 50 Hz, 40% duty cycle, 12 Volt square wave to light the high beams as DRLs. The dimmed light is slightly yellowish and has some flicker.

Connecting Pin 5 (.5 GN) to +12V draws 1.3 mA and turns on the DRLs. The DRL duty cycle, however, depends on the input source impedance. Raising it to ca. 200 Ω and then gradually to ca. 6 KΩ perceptibly increases the on-time to 100%, before the DRLs go off.

Disconnecting pin 5 while the DRLs are on (e.g., by opening the DRL switch) will make the high beams briefly flare up before they go off – a sort of incandescent flipping of the headlights reminiscent of a 1980's car. If this is aesthetically objectionable, a 330 Ω, 2 W load resistor between pin 5 and ground will quell the flare.

Connecting pin 1 (.5 GE) to +12V draws 3.7 mA and turns off the DRLs.

Connecting pin 8 (.35 WS) to +12V draws 3.8 mA and turns the high beams 100% on, independent of the voltages on pins 1 and 5.
Copyright © 2009, 2011 by John Firestone