After sitting for 4 months, toyhauler has no lights after hooking up..  3 day before departure.

Anyone suggest a url with trouble shooting steps?  Never tried fixing anything like this

No lights period? Need a little more info. Basics are check trailer light connection on vehicle and make sure you have voltage on the pins. Wiring diagrams and pinouts are findable on the internet. If vehicle ok, hook up and start checking for voltage at lights. Pull a cover off taillight, pull bulb, Check carefully from contacts in socket to socket body. Don't short the contacts to the body! No voltage there, start looking at trailer light connector, a fuse panel somewhere. Voltage at light socket, you probably have a bad bulb.If you don't have a tester, they're available from auto parts stors, harbor freight, etc. Thats a start. Hope this helps.

 rebar, on 02 August 2012 - 07:31 PM, said:

All interior lights, or tail lamp illumination?

It they all went away, not a single one works, look to the power source, not an isolated circuit in the trailer.

Edited by toyota_mdt_tech, 03 August 2012 - 06:21 AM.

Since he stated he had no lights after hooking up, I'm assuming he means his traveling lights (brake, turn, tail).

I have all lights working except the running lights now..  Trailer used to have 7 prong plug but was modified to fit my older truck with a 6 pin.  Ground wire not used.  If I had a problem with the ground, none of the lights would work.. Correct?


The running light pin is hot when I turn the lights on.   I faked voltage with the trailer battery and the running lights work..  Plug it in to the hot pin on the bumper plug and nothing..  I had a electrician shake his head and give up..  Along with a few friends who were baffled when I demonstrated the lights working off the trailer battery but not with the truck power..

I am so screwed..  Iv been preparing for this trip to Colorado for a long time and now this..

You need the ground. You should be able to connect the trailer lights connector to your vehicle with out being hitched up and all the lights should work. If not you have a wiring issue. You should not depend on ground through the hitch. Check your PM's.

clean all connections in the plug and socket, carefully take a small eyeglass screwdriver and place it in the slot of each pin on the socket and spread the pin open slightly.Carefull and not much the pins do break, basicly just stick the screwdriver in just just enough to say it is in. Confirm power at each pin as it is supposed to be. Park the truck next to the trailer and hook up the plug if nothing use a jumper cable and jump from the trailer frame to the truck frame if lights work definately ground issue. If no lights and the plug is servicable  check form poor connection, then see if there is a junction box , then look for broken harness.

the stranger the problem the more than likely it is a bad ground.  if you have a double filament bulb for the tail lights  the turn signals could be back feeding thru the running lights  appearing to flash but very dim.   If the body lights and turn signals are on and the body light flash the opposite of the turn signals that is your problem.    6 wire connector should be enough, 1 ground ,2 running lights,3 left turn/brake,4right turn/ brake,5 electric brake,6 auxilary

Thanks everyone.
Iv decided to start from scratch and rip out the old plugs and replace them with 7 prong even though I have voltage on the truck pins when Im done at work today.  The splice connectors are old and I may not be getting full voltage/amperage.

Whats the best type of connector when installing the new truck receptacle?

 rebar, on 04 August 2012 - 09:37 AM, said:

what do you mean   how do you want the wires to fit in the socket?  I prefer to have a screw type connection  and the wires stripped about a 1/4"  and the bare end soldered to help fight corrosion  and the lead giving a soft bed  for the clamp or screw to squeeze down onto,  that and some diealectric grease slathered over everything to help more with the corrosion.  helps make it servicable  4 years from now  if you have another issue.

 jsantapau, on 04 August 2012 - 09:58 AM, said:

No..  Im talking about the truck side.  Doesn't the truck receptacle have leads coming off each prong?  Or is it like the trailer male plug where you have to land wires?

you cold probably get either if you look hard enough   "landing" the wires tend to be more readily available  but if you find a molded unit  I would think that is better if you solder and heat shrink the wires

My luck,  I'll find a plastic deal not worth a crap and will have to buy 7 different colors of wire..  Then replace it again next year.   Is it Friday the 13th?

Thanks everyone!  

On top of my lights not working.. I jumped out of the back of the toy-hauler and landed on a uneven surface trying to hurry. Twisted my ankle, heard a pop and my foot started to hurt. Two hours later, I could barely hobbled into ER. I sat there for three hours and finally blew a gasket and let the staff know, along with everyone in the reception area, how happy I was. My Sisters a Doctor there..
So I was blaming my Friday the 13th birthday on the whole deal, but looks like my luck has changed! Ripped the old wiring out and installed new. I'm a expert at trailer lights now..

Lights! Camera! Action! Colorado here I come and I'm outta here!

Edited by rebar, 05 August 2012 - 03:38 AM.

 rebar, on 04 August 2012 - 09:37 AM, said:

I would do the same. I suspect its still a poor ground through the trailer ball and probably would come around once you started down the road. But its not a good idea to rely on the trailer ball for ground. You need a good ground for the brakes to work too. Good idea, swapping it all over to 7 pins.

No problems all the way here(pitkin co) until Monarch pass.  I was doing 15mph and my clutch fluid boiled or something and lost it.  Stopped middle of monarch pass..Learned some new words..  lol Regained clutch and made it but I need something smaller..  Like a 4x4 van,,  Any trades?