Trailer wiring

[Ace]

New trailer has brake, tail, and turn signals all in one light. My bus, a 92 h3-40 prevost has independent brake and independent turn signals. I can get running lights and turn signals on trailer but no brake lights.
Previously someone else installed a Hopkins convertor. It went bad and I installed another. It to went bad so yet another but a mechanic installed this one and before I got home it was melted.
Today I bought yet another one and decided to start from scratch and ti find pout exactly what I was dealing with. Pretty simple install With not so good instructions and results have a lot to be desired.
Anyway, I'm back to square one with just running lights and turn signals on trailer and no brake lights. I noticed the converter was getting hot and this is wired at the same location as before.
Doing some prior testing with engine in bus running, aired up, parking brake released and foot pedal applied, I started probing wires that are obviously going to the brake lights on the bus. The tester lights. Taking got of the brake pedal, turns tester light off. So more I figure I have the right wire to tap into! Not so!
So here I am, asking your advice. What am I missing!
I know a lot of trailers are being pulled by buses with independent lights. How?
Thanks....before it goes up in smoke!
Ace

[Jerry32]

What about Gumpy's converter. I built one and it has been working for four years now with only one blown relay due to a short in the wiring

[robertglines1]

I'm with Jerry   done it twice on two differant coaches.  last one the 89 prevost.   Bob

[rv_safetyman]

This comes up frequently.  The last one was only a week or two ago:

http://www.busconversions.com/bbs/index.php?topic=21827.0

Here is a copy of my reply to on that thread:

This subject comes up every once in a while and always starts out:  I am leaving tomorrow and I need a trailer connection that will convert a 5 wire system to 4 wire system and 24V to 12V    It always seems to get overlooked until the last minute.

In the March 2009 my article on the subject was published.  It contains quite a bit of detail of what is involved in doing the job correctly - at least in the opinion of Sean Welsh, Craig Shepard, Jack Conrad, and myself.  I present the best of all those folk's designs in the article.  More importantly, I list sources for the relays (including 24 volt).

For those of you who plan to tow and want to plan ahead, contact BCM and get a copy of the magazine.

Jim

As I read my post, it sounded a bit uppity. I did not mean it to be.  Ace, at least you are ahead of the game and not leaving tomorrow

The commercial 5 to 4 conversion products typically have very short lives.  Using relays makes a very robust system.

Jim

[white-eagle]

Ace, i think Susan put the garbage can on your head and you just can't see the solution.  I'm surprised with all you've done, this simple lighting thing has you under a can  .

Go to Walmart, take some pics, Re-read Jim's post, pop some kettle-korn and relax.  Then later, hook it up, try it out, then take Susan to Walmart and wait for a chance to pop the can trick again.

It's all fun.  See you in December.

[Ace]

Ok ive read your replies and thank you but, after reading the detailed description on gimps site, and the most recent post regarding this, they tend to mention converting 24v to 12v. This is not what I'm trying to do. My bus is 12v at the rear lights and so is my trailer. The issue is independent lighting on the bus to combined lighting on the trailer.
Do I still need all that is mentioned in gumpys article or is there a simpler solution?
Tom, that game is over. They now have clear buckets. Someone else must have complained! As for kettle corn? Possibly next Friday night but Dont tell anyone. I've been labeled as a Carny over at I@ns board for doing it.
Oh and Jim, although this may have been discussed recently, a lot of post go UN read by me since I don't frequent the boards regularly.

[Seayfam]

I vote for using relays... This is how I wired my bus, I have had no problems with it yet. I always have a trailer behind me or the toad.
I read here someware about two weeks ago, someone said there just aren't enough pictures on this forum. So here is a pic of how I wired mine.

[white-eagle]

Ace, sorry about the clear buckets and losing the fun you had with Susan. Give her my condolences.

you have 12V?  So do I.  i just hooked a separate set of magnetic lights to my van.  Did it by using a connector block where i spliced in the turn signal, lights and brake lights to a 4 wire that goes back to the mag lights.  when i turn on the turn signals or warnings, they flash.  when i turn on the lights, they are there, but not as bright as when the brakes or turn signals are on.  No converter to melt.  mine went to defect hell also.  this seems to work.  i gave up on connecting separate lights, and i don't like messing with the existing van lights that work until i touched them, so the extra $30 for separate magnetic lights works for me.

i can see them in the camera, so i know they are working, another benefit.

[Nick Badame Refrig/ACC]

Hi Ace,

It sounds to me that you just need a tail light Converter which is sold almost everywhere.

This converter will combine your seprate turn signal/break lights together for trailer use.

You also need to run a seprate trailer break wire from a break controler.

Give me a call if you need to.
Nick-

[bobofthenorth]

Ok ive read your replies and thank you but, after reading the detailed description on gimps site, and the most recent post regarding this, they tend to mention converting 24v to 12v. This is not what I'm trying to do. My bus is 12v at the rear lights and so is my trailer. The issue is independent lighting on the bus to combined lighting on the trailer.
Do I still need all that is mentioned in gumpys article or is there a simpler solution?
................

The converters you have already tried use diodes to isolate the brake from the signal on the bus side.  You've already proved those systems don't work so what the guys are saying is that relays are the way to go.  It may look complicated but you're just driving four normally open switches with input from the signal lights, the brake lights and the clearance lights.  The difference from the converters you have been trying to use is that the relays should be more robust.  I'm not sure why the converters aren't working for you - about the only reason I can think of would be that your trailer has a particularly heavy draw which is exceeding what the converter is capable of passing.

[Nick Badame Refrig/ACC]

Ace,

Also, I don't think you need to worry about trailer brakes.

I tow my 16' enclosed trailer to the track a couple times a month and my bus don't even know it's there.

Just make sure the break away is working for legal reasons..

Nick-

[Jerry32]

ACE just putin 12V relays in the curcuit and you got a converter that will do what you need I have done it both ways as when I had a 12 v rig I still used the relay system Jerry

[Oonrahnjay]

"My way" is separate bulbs for tail, brake, and turn on the toad.  But I'm starting from scratch and that's the way that works best for me.  If somebody already has equipment that's 5/4, different story.

[Seayfam]

"My way" is separate bulbs for tail, brake, and turn on the toad.  But I'm starting from scratch and that's the way that works best for me.  If somebody already has equipment that's 5/4, different story.

The only problem with wiring it that way is... if you ever want to hook up to another trailer or toad, your going to have a problem. Wiring relays is really easy and you can go from 12v to 12v or you can go 24v to 12v really easy. I like to use relays and a good 7pin plug on the bus, then you can get any adapter you may need to go from your bus to any trailer or toad you may want to tow.

[Oonrahnjay]

"My way" is separate bulbs for tail, brake, and turn on the toad.  But I'm starting from scratch and that's the way that works best for me.  If somebody already has equipment that's 5/4, different story.

The only problem with wiring it that way is... if you ever want to hook up to another trailer or toad, your going to have a problem. Wiring relays is really easy and you can go from 12v to 12v or you can go 24v to 12v really easy. I like to use relays and a good 7pin plug on the bus, then you can get any adapter you may need to go from your bus to any trailer or toad you may want to tow.

   Yes, but my bus, toad, car and trailer are all already 5/5.  I *might* need to add something else (in fact, I'm already thinking about a little relay box, just for the unusual need) but it shouldn't be frequent.