3 to 2 wire converter for trailer wiring

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Forum Name: General Discussion
Forum Discription: General Mobile Electronics Questions and Answers
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=121817
Printed Date: June 03, 2024 at 10:57 AM

Topic: 3 to 2 wire converter for trailer wiring

Posted By: jcriii
Subject: 3 to 2 wire converter for trailer wiring
Date Posted: May 13, 2010 at 12:40 PM

Can I build a converter with diodes?

My 1997 toyota tacoma has a three wire system with seperate stop and turn circuits. My small trailer has a two wire system with a combined stop turn circuit. I have been buying a reese converter/plug (part # 74672) for about $30. Due to the beach environment my truck lives in they do not last more than a year. The contacts on the plug corode, break or otherwise wear out. What I want to do is use 3 diodes, one on each turn signal wire and one on the stop wire so that I can conbine the wires on my truck and use a standard trailer plug that is cheaper to replace. My thinking is that the diodes will prevent the current from flowing from the stop circuit to the turn circuit on my truck and allow my trailer lights to work properly. Will this work and what kind of diodes should I use?

Thanks

Replies:

Posted By: oldspark
Date Posted: May 13, 2010 at 9:17 PM

But they won't flash when the stop lights are on.
Its that what you want?

Posted By: jcriii
Date Posted: May 14, 2010 at 11:09 AM

Nope, I wanted the turn signal to work with the brakes on. Now that you point that out it seams obvious why it would not work. I will use relays instead. Thanks for your help!

Posted By: oldspark
Date Posted: May 14, 2010 at 7:50 PM

LOL! If only you knew how much time I have wasted on the same!
Entire documents with diagrams until some error becomes obvious.

A few months back I though I had a perfect solution involving ONLY one JFET and resistor per side until I clicked that the FET has to carry the full current of the flasher bulb. (I couldn't understand why I hadn't thought of hat solution years earlier.)

So the solution remains unchanged - a DPDT relay per side.