trailer lights... part 2

[Bryan]

hey guys, some of you may remember the post a few weeks ago regarding trying to hook up trailer lights. I started a new thread because some of my issues were fixed and wanted to skip past all of that. Long story short, I ran new wires from the side driver panel to the rear for markers, blinkers and brakes. I was getting 9 volts to the tail lights before, now I'm getting 11 volts (with engine off), so my lights are much brighter, and the trailer I have hooked to it is also MUCH MUCH brighter as far as markers go. But now I have a strange issue... here are a couple things that have happened...

-the blinkers on the trailer are so dim you can't really see them,
-when I turned on the right blinker, all the markers on the bus and trailer briefly would turn off and then back on, off and then back on... (circuit breaker maybe?)
-when the markers are turned off, and I hit the brakes, there is a delay before the brakes light up on the trailer... see this video... Trailer brake lights

I have wired trailer lights before so I'm pretty sure I wired it correctly, but there only thing I used that I've never used before is a 5 to 4 wire converter, since the bus has separate lights/wires for brakes and blinkers, and the trailer uses the same lights for brakes and blinkers. I don't know if this has anything to do with it, if so I would need to add lights to my trailer to separate the blinkers from the brakes. But this still doesn't explain the markers completely shutting off briefly.

One last thing I would like to add... when the engine is idling there is a gentle flicker in all of my lights if you watch real closely, in fact you can almost hear the engine going along with it, like the sound of the engine is barely changing as the lights change... barely. Thanks for your help guys!

[rgrauto]

Bryan make sure that you have a good ground for the trailer not just the trailer ball. If your bus is 12 volt you can buy a trailer tail light converter like used for Toyota/Nissan trucks that use separate lights for brake and turn signal lights to stop feedback between the lights. If bus is 24 volt then you use relays ,the number escapes me at this moment but maybe someone has the number.

[Bryan]

Thanks! I think that is the converter that I'm using already. Tonight I bypassed the converter and it worked fine on either brakes or blinkers, of course I can't do both at the same time, so I've about decided in just going to buy another separate pair of lights on the trailer to use just as brakes.

[akroyaleagle]

Adding another pair of lights is the answer.

I have done that to all of my trailers and solved all the problems.

(Course it took me several converters $$$ to figure it out)

[belfert]

If you're not using a powered converter I would get one that is powered.  You can also make your own with a few relays.

[gumpy]

Curious, did you try any of this with the bus running and generating power? I suspect the 11 volts you are seeing at the converter is the problem.
Maybe try with the alternator running at 14 volts and see what happens.

There are plans on my website for a relay based converter. Many others available on the board, too.

[Nick Badame Refrig/ACC]

Hi Bryan,

I have been using Gumpy's  24 to 12v relay set up for 5/6 years now and love it..
http://www.gumpydog.com/Bus/MC9_WIP/Electrical/Tail_Light_Converter/tail_light_converter.htm

Before his relays, I would install 24v bulbs in whatever I was towing and it was a real PITA.

At least I can tow anything now and not have to worry about voltages.

Good Luck
Nick-

[Bryan]

you guys may need to school me just a little. Remember I'm a newbie still    I was assuming that the bus was 12 volts simply because when I put a voltage reader to the battery it's approx 12 volts. What makes a 24 volt system? And how do I know what I have? Thanks!

[Nick Badame Refrig/ACC]

you guys may need to school me just a little. Remember I'm a newbie still    I was assuming that the bus was 12 volts simply because when I put a voltage reader to the battery it's approx 12 volts. What makes a 24 volt system? And how do I know what I have? Thanks!

Ooowa... That's a problem.. Lol

Bryan, if you have two 12v start batteries, that might be your sign..

I would start with your manual and then simply read the voltage on your starter. I'm pretty sure your

4107 is a 24v system. If so, could be why your having issues with trailer lights... You are probably

burning up the converter.

Nick-

[gumpy]

Ok, wow! This could be a problem.

I'm not a GM guy, so I was assuming you knew how your own bus is configured, either 12v or 24v.

If a 4107 is 24v, then we need to back up and start over, because your 12v trailer (and converter) is NOT compatible.

[Bryan]

According to Wikipedia... "The PD-4903 was the first GM bus to use a 24 volt electrical system."

My 4107 was before the 4903 correct?

[wildbob24]

The 4107 is 12 volts. It uses 2 12 volt batteries wired in parallel.

Bob

[Bryan]

Good to know! Thanks Bob! I will proceed with adding an extra pair of lights to the trailer 😃

[gumpy]

Did you try it with the bus running?

[PP]

I had the same exact problems with my bus and it's definitely 24V. Turn signals were so weak you couldn't tell they were blinking and I know I had the correct converter in line. I eventually gave up and wired extra lights in the housing on the Liberty and now with the Mini I have bypassed the tail lights altogether and mounted LEDs in the bumper on either side of the backup light. They work great in any light conditions and I get comments all the time from Mini enthusiasts asking what the lights in the rear are for when we're not towing.
Will