Having electrical problems with wiring the trailer (again...what else is new)

[ilyafish]

Okay, so this one is a little more simple...i just cant diagnose it.  I am having issues with my brake light wiring on the trailer.  I am running the wiring to the brake lights from the remote control box in the rear of the bus.  Here is what is happening....if i run a wire from the left stop stud on the control box to the left stop on the trailer, and a wire from the right stop of the bus to the right stop of the trailer...only the left stop works (the right one remains dim as it is getting power from the running lights, but the filament for the brake doesnt light up).  This setup works for about 15-20 seconds before the brake lights go off (circuit breaker).  If i take the 2 wires from the trailer stop lights (yellow and green), fuse them together with the right stop (havent tried the left stop) from the control box, both stop lights on the trailer work correctly....but also 15-20 seconds before the stop lights go off (circuit breaker again).  If i disconnect both stop lights for the trailer from the bus, the breaker for the stop lights on the bus no longer flips.  So i am assuming that something is crossed.  However i dont understand why they work when fused with the one wire from the bus, though when hooked up 'correctly' left to left, right to right only the left works.

I am running out of ideas!

[Van]

Are you possibly feeding 24 volt to the 12 volt lights,are the lights led?What about the ground,good connection.How many volts are at the rear bus studs?Proper voltage,good ground connection to trailer,also make sure the wire configuration on the trailer and bus socket jive.Best I can think of right now ,start at the bus and move to the trailer,got a volt meter?good luck.ps make sure to check the bulb numbers and the bases of the bulbs for proper application

[Van]

Are you possibly feeding 24 volt to the 12 volt lights,are the lights led?What about the ground,good connection.How many volts are at the rear bus studs?Proper voltage,good ground connection to trailer,also make sure the wire configuration on the trailer and bus socket jive.Best I can think of right now ,start at the bus and move to the trailer,got a volt meter?good luck.ps make sure to check the bulb numbers and the bases of the bulbs for proper application ;)almost forgot check the bulb sockets too

[ilyafish]

the trailer lights are 24v, not led.   24 volts at rear bus studs.  got a volt meter...everything checks out.  ill run over everything again, just to be sure.  as far as the bulbs go....theres 2 different kinds of dual filament bulbs....one kind has 2 small 'prongs' along the side on the bottom that are on the same level, the other kind has ones that are offset.  the trailer takes ones that are offset.  i only have one of these on hand, and i took a bulb that has the 'prongs' on the same level and made it work....figured it would not make a difference, as long as it worked.  would this pose a problem?

[Tenor]

check the position of the studs against the position of the electrical contacts.  They may be different and not lining up with the contacts in the socket.

Good Luck!
Glenn

[Fredward]

I'm not following the exact sequence very well. But doesn't the MCI-9 have separate tail, stop and signal bulbs and circuits? In which case, you need separate signal and stop bulbs in the trailer or a device to isolate them from each other?

Fred

[Tenor]

Right Said Fred!  Wait, was'nt that a musical group?   

Glenn

[ilyafish]

To save myself a headache, I'm going to consolidate all our equipment to fit in the bays and tackle this when we get back (we leave tomorrow). In the meantime I'm going to have a friend sell it (I currently have a single axle 6x12 and upgrading to a tandem 7x16). Thanks alot for your help guys...I think next time I do this I'll take it down to one of the jersey guys here

[Hartley]

Unless you have done the relay conversion to combine the
actions of the stop and turn signals, You have a problem.

The Brake light and Turn signal lines are separate circuits on the MCI 9
coaches. If you hook them together you will trip breakers and have all sorts
of issues.

1-Wire to feed left and right brake lights
and 2 wires "TURN" (one for left turn and one for right turn)
A separate wire for "running" lights.
and last but not least the grounding ciruit...(for all lights)

Thats 5 wires. Plus your power feed and electric brake circuit. ( total of 7 wires )

Then if you have backup lights add the 8th wire.

Now enter the trailer wiring. If it is wired for a combined brake/turn setup and you are
trying to "rig" dual filament (24 volt) bulbs in order to "cheat" then you may have issues with
getting it to work.

I have noticed that most of the dual filament 24 volt bulbs like used in the MCI are not
the same as a regular trailer or stop/run bulbs. The ground and common elements are
internally wired different dependent upon original application. Some are parrallel filaments and others are series filaments. ( Not the same! )..

Do yourself a favor and use "SEANS" relay system to combine stop and turn before the trailer and also to power the running lights. Then you can setup either 12 volt or standard 24 volt lights for the trailer with a standard Trailer connector and wiring. It works every time and once and for all (trailers)....

Dave....

[rv_safetyman]

I just published an article on this subject in Bus Conversion Mag. 

I worked with Craig, Sean, and Jack Conrad.  One of the things that you should think about, is that the relays should have a diode.  In the article, I list the correct relays and sources.  I think Sean updated his drawing to include the diode relay and the polarity sensitive wiring.

I will try to post the article on our website in the next few days.

Jim

[Van]

Maybe this will help some what on the trailer side.
http://hopkinstowingsolutions.com/doc/trailer_wiring_codes.pdf