Trailer lights need to warm up?

[Volffas]

When I hook my boat and trailer to my truck the lights never seem to work right away. I really don't understand why this is. To me, it seems like as soon as I plug in the electric to the trailer, the lights should come on at full brightness. But it never fails they are always very dim at first, but after 10 minutes or so they will light up like they should.

Has anyone else had this problem? What could be causing it?

 

[Murf'n'surf]

You have rusty balls.




Ha! Or just one.... The trailer does not have a good ground. Usually after moving and knocking off some rust or film, the trailer grounds well and the lights come on.

 

[bronze_10]

Agreed... ground issue..

 

[itsdgm]

On our vintage boats. The ground is terrible. In essence, the ground from the tow vehicle is grounded before the swing away. Then all the lights are grounded to the trailer frame after that. Over time, the hinge on the swing away looses connectivity due to corrosion and road grime. The easiest way to remedy this is to run a wire from the stock ground (before the swing away), through the swing away and secure it to the ground on the first running light down the frame. Hope that helps you out.

 

[scokill]

Ground wire at front of trailer, and there are different points where light grounds are attached. Remove and and clean trailer with wire brush where there are contacts and you may have to replace rusted nuts and/or studs. I believe there are two common grounds for each side that attach to the trailer at the rear lights. Brown wire if memory serves me.

 

[KXCam22]

Also put a ground jumper across the hitch pivot on the trailer so that the lights are grounded to the part of the trailer that touches the truck. I went as far as to run a dedicated ground wire down each side of the trailer. Now all my lighting issues are long gone. Cam.

 

[Volffas]

Thank you for all of the replies! Hopefully I will have some time next weekend to work this out. I couldn't figure out what the issue was and it was driving me nuts.

My hitch ball is brand new, but there is lots of rust on the trailer tongue, so I'm sure that is the issue. Just like @Murf'n'surf said, once the trailer moves around and knocks some of the rust off, the lights work flawlessly.

 

[Bill D]

Couldn't agree more.

I hate dealing with trailer lighting issues so much that one of my first boat projects was to rewire the entire thing... I replaced the goofy 5-pin harness with a 7-pin round, ran all new wires with dedicated grounds, and soldered and shrink wrapped every connection. Took about 3 hours, but I shouldn't have any more problems.

... and while I was at it I figured I should install some LED runway lights.

 

[Marvin willis]

I think you jinxed me. I never had lighting issues til reading this post. Thanks a lot

 

[Scottintexas]

I also ran a jumper across the folding tongue pivot and haven't had a problem since,

 

[subysti]

Could also be the power coming from the truck itself. My VW Toureg would do weird things like turn off the lights if it didn't think they were plugged in, then turn them on. sometimes they were dim if there was a bad bulb and it wouldn't like LED lights at all. If you have a "normal" tow vehicle probably not but if its some "euro" truck you never know......

 

[Marvin willis]

My lights worked great on the way to vacation but when we got there I had my hazards on it sounded like someone was tapping the trailer with a hammer. When I hooked back up a week later had no lights for about 5 mins

 

[jawsf16]

It's almost always the ground on the MFI trailers I have had...

 

[Murf'n'surf]

My lights worked great on the way to vacation but when we got there I had my hazards on it sounded like someone was tapping the trailer with a hammer. When I hooked back up a week later had no lights for about 5 mins

Your tow vehicle might have a seperate relay for the trailer lights

 

[JetPowered]

Could also be the power coming from the truck itself. My VW Toureg would do weird things like turn off the lights if it didn't think they were plugged in, then turn them on. sometimes they were dim if there was a bad bulb and it wouldn't like LED lights at all. If you have a "normal" tow vehicle probably not but if its some "euro" truck you never know......

You don't know that half of it (having owned three Touareg's in 12 years). My current V10 doesn't play well with any LED lights, so I did order a high resistance LED compatible 7 to 5 adapter from eTrailer that helps out with the errors in the dash display. At least the brake lights work all the time now.

 

[Julian]

You don't know that half of it (having owned three Touareg's in 12 years). My current V10 doesn't play well with any LED lights, so I did order a high resistance LED compatible 7 to 5 adapter from eTrailer that helps out with the errors in the dash display. At least the brake lights work all the time now.

Huh... my Audi Q7 has never had any issues....I'm amazed when it tells me that a light is out....like it did at Shelbyville last year....and it as right...bulb was blown and the old boats had sealed lights. I replaced with LED and no issues since (but now you'll have me wondering!)

 

[veedubtek]

Huh... my Audi Q7 has never had any issues....I'm amazed when it tells me that a light is out....like it did at Shelbyville last year....and it as right...bulb was blown and the old boats had sealed lights. I replaced with LED and no issues since (but now you'll have me wondering!)

It will. Pending what year it is anyway. Different than the tow-rag probs though. The actual taillight harness in the Q7's was shit.

 

[Julian]

It will. Pending what year it is anyway. Different than the tow-rag probs though. The actual taillight harness in the Q7's was shit.

It is a 2011....and knock on wood....its had no issues at all!

 

[veedubtek]

Almost picked up an '11 Q7 TDI early this year. Was the same price as my truck, except my truck was brand new and the Q7 had 80K miles. Even as big a vw/audi fanboy I am, I just couldn't justify it. Also explains why my truck only has 3K miles on it now, I hate driving it. heh. Only when I have to (only when I'm taking the boat out). Super nice rig that Q7 is.