Here's one that I can't figure out. I have a truck and a van. The van has separate signal and tail lights so it has an electronic adapter for the trailer lights.
The trailer lights all work fine with the truck so I know the wires and ground are good. On the van, only the tail lights work. However, I have juice at the van's light plug for both turn signals but it just doesn't get through the wires to the trailer lights (yet it works fine with the truck).

The van light plug lights my test light ok but it flashes too fast for my meter to see if it's getting full voltage from the adapter. I'm suspecting that the electronic adapater isn't putting out enough voltage or amperage.

Any suggestions?

Pull with the truck.

Add this to your favorites and print out. Sure helps.

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

Your turn signal filament is also your brake light. Your running lights (tail lights) are the other filament. Does your brake lights work?

What type of van, and does it have LED tail lights?

Patrick F. McManus once had a pretty funny column (in Outdoor Life perhaps?) that dealt with trailer wiring -- and the joys of lying on the cold wet ground under your truck hollering to your helper "Is the brake light on now?".

Reading it won't give you any new insights into your specific problem, but it may make you laugh.

John

It's titled 'Trailer Trials'. It's not all that far off the track.

Ah, thanks!

With your info, I could find that this story appeared in his 1985 book "The Grasshopper Trap".

Hard to believe that it was that many years ago! I can recall laughing my way through that book...

Actually, I mostly laughed through all of his books! I particularly remember my Grandmother giving me his book "A Fine and Pleasant Misery" for a Christmas present in 1978 or 1979.

I pretty much sat down and read it cover to cover on Christmas day and didn't really socialize that much. My parents said to put the book down -- but at least my Grandmother sure knew that she hit a home run in buying me that book!

Oops, sorry for the topic hi-jack! So, below, I include ALL of my knowledge on trailer lights that will help you.











John

Had some sorta utility trailer since the mid 60s and can appreciate light woes and gremlins inherent in them. More than once I've ripped things off and started over. And eventually the gremlins re-infest things.

Last year I pulled my double axle flatbed up to hunting camp and fetched a mess of firewood home on it. Had no tailights, but the stop/signal lights worked fine.

Coupla weeks ago hauled it to a local woodlot to haul firewood home. This time around, tailights worked fine, had no stop/signal lights. What-efn-ever. It's out back again next to the wood pile.

Bad grounds probably cause 90% of trailer light problems. Tomorrow I need to get it up on jacks and take a good look underneath. The tail lights work but the brighter turn signals might not have enough ground to work. My test light takes almost no juice at all so even the slightest ground will let it light.

Get a test light and start poking through the wire till you find the broken circuit. Or if it is run through conduit you might just run a new wire...

bad grounds are a good place to start. try turning on one turn signal and looking at the other in the dark or low light. You might see the one that is not on flashing. that shows current using that circuit to get to ground. Also i havent messed with newer cars but does your van use a turn signal flasher unit like older vehicles. Vehicles not usually meant for towing had a light duty unit that wouldnt power any extra lights very well.

Guessing it's a Jap van?

The amber turns seem to be a constant problem with trailer lights.

All trailer lights are part time

Yet they always work when you leave home...

I have a 1972 tri axle flat bed. About every five years, I pull all the wire and redo it. Saves me a lot of grief .

Not always. That's my problem now.

Then I guess you can't use that excuse when asked by the fuzz.

The Microsoft solution to trailer lights?