Re: [MV] Electrical Problem/Trailer Hookups

From: GOTAM35 (gotam35@sc.rr.com)
Date: Fri Apr 25 2003 - 18:01:29 PDT


----- Original Message -----
From: "Marc Strangfeld" <curlyjoe98@yahoo.com>

> Does anybody have a good way to wire 12 volt trailer
> lights? I plan on towing a camper with the M35 and
> could use some advice. A thought was to replace the
> bulbs with 24 volt ones but the electric brakes are
> still an issue. Standard Ignition sells a $100 24 to
> 12 converter but it is only good for 4 amps. I really
> don't want to change the truck over and I want to do
> it right to avoid problems later. Any advice is
> greatly appreciated.
>

Ok, here's what I have done and also what I would like to do.

First off, I installed a 24v to 12v transformer that is good for about 15
amps. I used 3 little 24 volt coil relays that are energized by my rear
tail and turn signal wires that then provide 12 volts to a regular truck
plug on the back of my truck (M35A2). I have broke the grounds on the relay
coils with a switch so the little buggers don't click every time I use the
turn signals/ brakes, just when I have a trailer hooked up. So far so good.

As for the brakes I now use a trailer with air brakes. Can't beat that. I
was trying to design a relay that worked either with a pressure switch from
the air or a hot wire from the brake switch that would put a pre-determined,
resistered feed strait to the brake magnets. If I understand it correctly
the magnets will work this way. You wouldn't really need to meter this feed
much anyway. If you are hauling an empty load, just switch off the brakes.
As a last resort put a brake box on the dash and make it look like it works.
If anyone tries something like this and it works, let the rest of us know.

Joe Trapp



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