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Anyone know how to wire the rear fog lights to function as additional brake lights?

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Old 07-28-2000, 10:36 AM
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Default Anyone know how to wire the rear fog lights to function as additional brake lights?

<p>2001 1.8TMSP
Ebony Pearl with black L-ette
Clear Corner mod
5% tints
2 10" MTX Subs w/MTX amp
Drive 1000 miles a week & love it.
Old 07-28-2000, 12:25 PM
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Default if you take a look at the bulb assembly....

the bottom bulb has connections for the brake lights 21w. tap into. then you will have to make a break in the connection to the rear fog light and connect a diode to prevent reverse current from flowing back to the fog relay. then connect the tap of the brake light to the fog. you will need to know the polarity of each lead to decide which way the diode goes.

if that makes sense, great. otherwise email me i'll walk you though it. haven't done it myself, i wouldn't but that's how i would if i did.<p>2000 A4 1.8TQMS
Old 07-28-2000, 12:33 PM
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Default somethings to watch out for....

if you are going to wire up another set of 21w bulbs. not sure how much the brake and rear fog relay can handle.

i imaging it is within limits.

another trick would be to tape off or file off the 21w contact on the brake light bulb and use the tap that i explained in the previous post as power to your new set. this would keep the same current draw regardless.

the diode is still key to preventing any frying. my $0.02<p>2000 A4 1.8TQMS
Old 07-28-2000, 02:37 PM
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Default Unless you still want rear fogs after turning them into additional brake lamps. . .

Hey There,

Unless you still want rear fogs after turning them into additional brake lamps, you don't need diodes. Just cut the positive feeding the fog and splice the positive for the brake light into it.

I have wired up my rear fogs as my brake lamps instead, not in conjunction with the OEM position. Reasons being that they are higher up, and totally separate from the taillamps so they're much easier to notice. When I turn on my rear fogs now, they actually light up the old brake lamp. To do it this way, just find the corresponding connectors in the taillamp harness and swap them.

Hope this helps<p>James Wu
<a href="http://vancouver.a4.org" target="_top">Vancouver A4 Club</a>
1998 Black on Black/Dove Grey Leather 1.8t
<a href="http://home.mdi.ca/james561" target="_top">James' Audi A4 Page</a>
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