Shoreland'r trailer wiring - How to troubleshoot? (need help) - Fixed

[RightStuff]

Yesterday coming home from the lake I was backing the trailer into the driveway and my wife noticed the center and right side of the trailer lights were not working (all light functions). So looking at the manual for my trailer I noticed that all the center/right light wires go down that right side (I think green and brown wire), so that isolated the issue to those wires. But after poking at a few things I wasn't able to figure out where the problem lies and then it got too dark... FYI, the trailer is a 2013 Shoreland'r without LED bulbs.

Here's what I checked/tried so far:

• Checked/reseeded connections @ truck and boat (at the trailer Y there are some connectors), it's a pretty new trailer so I didn't see any corrosion at any plug/connection.
• Hooked up voltmeter to truck plug and saw the voltage jump up/down on those plugs when the flashers were on.
• Checked trailer fuses in truck and those seemed good as well. So between that and the voltage change at the plug I kinda ruled out the truck, maybe there is something else to check here to be sure?
• Hooked up voltmeter to blinker/brake bulb with it removed. Saw a slight voltage jump with flashers on. I was testing the 1157 bulb housing (black on white ground wire, red on the inside/center connections of the bulb housing), not sure exactly what I should be seeing here, but looked like there was power getting that far back...
• Tested right blinker/brake bulb with a 9v battery and it still works/lights up, so that rules out that bulb. But maybe if another burnt out it would short the whole side of lights?

Left to try:

• Pull 3 center light assembly and check connections/voltage in there. Since this is linked to the right side I was thinking this morning maybe the ground is bad there?
• What other ideas do you have that I should to try?

Good news is my trailer is under warranty, but going to the dealer isn't very convenient so it would be nice to figure it out, I'm sure it's something simple/stupid...

 

[Kevin107]

I would pull the center lights out to check the bulbs and for corrosion. If there are signs of corrosion, it might short out whatever it's linked to. Hopefully, it's something simple. Good luck!

 

[Murf'n'surf]

Sounds like a bad ground. Look for a ground wire not connected to the frame.

 

[txav8r]

The Shorelandr wiring harness is nice. They use an actual ground wire front to back. The rear center lights on my trailer have a plug in off the end of the line at the left rear and do not come down the right side. I haven't checked to see if they are picking up ground for the harness at the truck connection, or if they are using a flimsy white wire to the frame. Either way, you have to have a good ground.

 

[RightStuff]

Thanks all!

Sounds good, I hope that's all it is, I'll try and take that off tonight and check it. Just strange that yours comes down the left side and not the right, maybe they did it differently with the 24' trailers? I did notice that the 2013 24' trailers have LEDs, so maybe that style is wired differently than the ones used for the 21 footers?

 

[txav8r]

My 2012 is LED also apparently.

 

[RightStuff]

Wanted to make sure I posted an update to this because I have the lights fixed now. I hate leaving these topics open, so just in case someone else runs in the same issue here's what I found...

So after much digging around with connections and testing every bulb on the trailer I could, I found that half of the large (1157) bulbs in the back was burnt out. I tested that bulb at the very beginning since that was the one that didn't work, but must have missed one of the 2 'modes' (high/low) on the bulb. Just a stupid mistake, but at least I know my trailer wiring inside and out now!

@txav8r - you were right, the center lights go down the left side of the trailer on mine too and branch off the left rear light wires just before the light housing, so no change there between the '24 and '21 trailers. Also they are all grounded back via the white wire in the front. I didn't find any 'flimsy' ground wires bolted directly to the trailer, that was the first place I looked because the center light for me was out too.

So now I have added switching out these stupid bulbs with all LEDs to hopefully prevent this in the future. Add one more mod to the list...

 

[txav8r]

Regardless, just glad you are back in business @RightStuff ...there is nothing more aggravating that electrical gremlins. So you found no frame grounding whatsoever and the entire ground connection of the trailer lights on the shorelandr runs from the ground connection to the vehicle, is that correct? I didn't remember seeing the telltale sign of the white wire on my new shorelandr, but I wasn't certain that it didn't exist internally somewhere in the frame. It does make more sense and probably is more reliable to not depend on things that can rust. I totally agree with your plan to replace them with LED's, they will just be much more reliable than the incadecents. Were all the bulbs in the rear center frame marker lights burned out or was it unplugged somehow? Glad your back up and well illuminated!

 

[RightStuff]

@txav8r - I did not find a single ground connection (like a bolt to the frame) on the white wire thru the whole trailer. The only ground there really was is in the Lt and Rt tail light assemblies attached to the metal bracket that held the 2 bulbs in there and that must be the ground for all of my lights that went out.

The strange thing with mine that really confused me is the center 3, side marker, right light, and all the dim (headlights on) lights went out together, but the left side blinker still worked. That was all caused by the dim half of the right side blinker bulb (the 1157 style one) going out, that was the only burn out I had. They must be tied to the same white ground wire? Just very strange... In the middle of all of this I was starting to question everything I knew about electrical circuits! (which isn't all that much to begin with). Just glad that was all it was and it saved me a long trip to the dealer to have them fix...