trailer wiring - be careful here!

[Mike Arman]

Sorry, we're not out of the woods yet (and I'm not trying to start a flame
war or anything).


>--__--__--
>
>Message: 5
>From: "James Marriott" <marriott at micron.net>
>To: <quattro at audifans.com>

>
>This problem has already been solved for $40 at any parts store.
>It is a combination of the $15 4/3-filament converter and a
>separate power supply wire (on the t44s available handily from
>the nearby battery).
>
>cu, James Marriott


James, I don't think that will work, because the 4/3-filament converter box
draws power from the car's lights and combines the signals to light the
trailer lights. Unless it has a separate power supply wire (and mine
doesn't), it will still melt the harness. If yours has a separate power
supply wire, please let me know who makes it and how much it costs, because
that box is then doing exactly what my (proposed) relays will do, and will
have the separate power supply as I want to use, too.


>
>--__--__--
>
>Message: 6
>Date: Sat, 05 May 2001 12:30:36 -0700
>From: Huw Powell <audi at mediaone.net>
>Reply-To: one at humanspeakers.com
>Organization: HUMAN Speakers
>To: Mike Arman <armanmik at n-jcenter.com>
>CC: quattro at audifans.com
>Subject: Re: trailer wiring  - be careful here!
>
>
>> We'll need a relay to work the brake lights, a relay to work the parking
>> lights, and a pair of relays to work the turn signals. Which immediately
>> brings us to another gotcha: Wiring the turn signal and brake light relays
>> in parallel will make the turn signal filament burn steadily when the
>> brakes are on, and wiring them separately will make the trailer's turn
>> signal flash in reverse to the car's signal. (car on, trailer off, trailer
>> on, car off.)
>
>one relay for each sides park/brake light will work if you use the cars
>turn signal and brake signal wires to trigger the relay.
>
>-- 
>Huw Powell
>

I don't see how you would wire this - first, you'd need a blocking diode so
the park light signal (which is on all the time) and the brake light signal
(which is on some of the time) will not interfere with each other. Once
these signals were isolated, if the park light was on, the bulb would be
lit all the time anyway, and adding the brake light signal won't do anything.

The problem is that US wired cars flash the brake light as a turn signal
(the 21 watt filament), while the park light (5 watt filament) stays on all
the time.

Relay needed for the park lights, one system.

Relay needed for each turn signal, two systems.

Relay needed for brake lights, one realy turns on both brake lights (which
are also used flashed as turn signals, and we can't do that).

My feeling is that the easiest way is a three lamp tail light array on the
trailer: Parking lights, turn signals, separate brake lights, same as we
have on the cars. Still need relays because of the skinny wires Audi sent us.



Best Regards,

Mike Arman