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Fri Jun 22, 2007 8:59 am

I am finishing up my westy trailer and need some help with wiring. My trailer uses bus tailights so I essentially would like to tap off my bus lights and wire them back to my trailer lights. I can use brass 1 male 2 female to jump the bus and trailer lights together. The problem I am realizing is that the trailer plug I have has 4 wires. 1 for ground, 1 for turning and 1 for brakes.

If I am correct I can jump the brake light wire off of one of the bus tailights and supply the two trailer brake lights. I can also do jump one of the bus running lights and supply my trailer running lights. I now will have two wires left 1 which will have to be my ground and the other for my turn signals. The problem I have is I will need two seperate wires for the turn signals as if I supply both trailer lights with one turn signal connection from the bus my blinkers will both blink when I hit left or right!
I know getting confusing.

Correct me if I am wrong but I could jump all the connections from one bus tailight(running,turn,brake) and supply both left and right trailer tailights with the same lights except for one trailer tailight which will get its own dedicated turn signal which I could jump just the turn signal from the other bus tailight so that I get that turn signal only on the other side of the trailer! Should I just buy a plug and make this happen or is there a more professional way!

I usually can figure these things out but, I am having trouble laying it out!!
Pics of setup!
[img]

Fri Jun 22, 2007 9:15 am

You need a 5 pin connecter.

http://www.etrailer.com/faq/wiring.aspx

Fri Jun 22, 2007 9:19 am

Either what Ted said or add a single wire for the ground and use the plug for stop,running,left,right.

Fri Jun 22, 2007 10:43 am

Thanks Guys! Just want to make sure I have a clear idea on how I am going to accomplish this. If I was to add a ground wire how would I do that! It is the plug itself that I am trying to ground correct?

Fri Jun 22, 2007 11:19 am

Don't have to ground the plug, just need an extra wire (with a disconnect) from the bus body to the tailight grounds.

Fri Jun 22, 2007 11:26 am

Where are the tailight grounds? Are you saying I could essentialy use my existing 4 wire harness for all the lights and make a seperate wire with a disconnect for the ground. I am still unclear where to put the ground wire?

I could attach it to a good metal ground on the bus and the other end I could attach to the tailight grounds wherever they are!

Fri Jun 22, 2007 11:51 am

Charles, reach inside the engine compartment passenger side. about 3 inches from the tail light holder there is a double male connector welded to the body. thats the ground. I also use that for my trailer 4 prong plug.

Fri Jun 22, 2007 12:08 pm

Thanks olddkp!!

Fri Jun 22, 2007 12:32 pm

I also pull a Harbor Freight Trailer with my bus. When I wired the lights, I also wanted to use backup lights on the trailer. I cut the four pin connector off of the HF wiring and added 2 more wires -- a ground and a backup + lead. I used a standard 6 pin connector to wire it all together. An advantage of this is when I pull my friends motorcycle trailer or loan my trailer to someone else, the wiring is all standard.

You can find these plugs and the "pigtail" for the trailer end at most FLAPS or RV stores. I think Walmart may also have them.

Steve

Fri Jun 22, 2007 1:08 pm

I guess my question was where are the grounds on my tailights. I now know where to ground the wire on the bus but where on the trailer tailight!

Fri Jun 22, 2007 1:10 pm

How did you run the wires out of the engine compartment? I have wanted to do it like you have it but can't find a way to keep the wires from getting scorched buy the exhaust.

Fri Jun 22, 2007 1:25 pm

The tailight ground terminals are inside the tailights, under the grey covers. Or if you still have wires hanging out it's the solid brown ones.

Fri Jun 22, 2007 1:30 pm

Yeah under the grey covers I have the bulb connections not sure which one is the ground?

Fri Jun 22, 2007 2:05 pm

You can ground all the lights to the frame and just have one + lead to run to each bulb. Then connect a ground wire to the tongue near the coupler and run that to the bus.

Steve

Fri Jun 22, 2007 2:08 pm

If I misunderstood the question and you need to know which terminal on the bulb is ground, just compare to the lights in your bus. On my '70, all the ground connections are daisy chained with one black wire. It's pretty easy to figure out.

Steve

Fri Jun 22, 2007 4:15 pm

Steve's right, find the terminal that connects to all the bulbs.

Fri Jun 22, 2007 5:09 pm

here is how i have mine hooked up.[img] the pic's are in my gallery

Sun Jun 24, 2007 5:35 am

redbus Steve wrote: I also pull a Harbor Freight Trailer with my bus. When I wired the lights, I also wanted to use backup lights on the trailer. I cut the four pin connector off of the HF wiring and added 2 more wires -- a ground and a backup + lead. I used a standard 6 pin connector to wire it all together. An advantage of this is when I pull my friends motorcycle trailer or loan my trailer to someone else, the wiring is all standard.

You can find these plugs and the "pigtail" for the trailer end at most FLAPS or RV stores. I think Walmart may also have them.

Steve

For a really comprehensive electrical towing socket & plug system, you could do no better than those used in Great Britain & Europe, as follows:

British & European, 12N standard 7-pole, electrical towing socket & plug, which traditionally serve all the road-vehicle lighting requirements (including reversing light and rear fog lamp), for a towed trailer, for which the following link shows the wiring circuit:

http://www.rydertowing.co.uk/trailer_towbar_wiring/12N_trailer_towbar_wiring.htm

The following link, shows the wiring circuit, for the similar looking, British & European, 12S supplementary 7-pole, electrical towing socket & plug, which serves other electrical requirements of a towed trailer or caravan, such as battery charging, interior lighting, refrigerator, etc:

http://www.rydertowing.co.uk/trailer_towbar_wiring/12S_trailer_towbar_wiring.htm

In Great Britain & European, the two pairs of matching 7-pin, 12N & 12S towing sockets & plugs, are being superceded by a single pair of matching, ISO 11446, 13-pin socket & plug, so both systems are still currently in use.

http://www.western-towing.co.uk/acatalog/Towbar_electrical_parts.html

http://www.rightconnections.co.uk/13pin-uk.htm

The following link shows the wiring circuit:

http://www.rydertowing.co.uk/trailer_towbar_wiring/13_Pin_trailer_towbar_wiring.htm

Regards.

Nigel A. Skeet

Sun Jun 24, 2007 1:32 pm

Ground is through the hitch, all the lights are grounded to the steel frame of the trailer. Since the battery is grounded to the body and frame of the bus, the trailer can be grounded to the frame through the hitch assembly. :wink: I hope that made sence... :?

Mon Sep 29, 2014 8:53 am

Sorry to resurrect an old thread, but I'm in the process of wiring up a Hella 7-pin trailer wiring sock and have the same question as the gentleman below:

kkirwin wrote: How did you run the wires out of the engine compartment? I have wanted to do it like you have it but can't find a way to keep the wires from getting scorched buy the exhaust.

I just don't see any great way to get the wires from the engine compartment to a socket I'd like to mount under my bumper without getting close to the exhaust. I've seen some pics that show a trailer plug hear the left taillight, which could be an option but I might then have to extend my trailer's plug cable to reach the longer distance.

Interested in any advice and/or photos you may have of your socket cable routing.

Thanks in advance!

- Doug :-)