2016 Forester MBS 2401s - LED Brake Light Will Not Turn Off

[kysunseekermbs]

Originally Posted by dukeboone

Interesting report kysunseekermbs, sounds like you're experiencing the exact same thing as me. I did find two grey connectors, a relay and something that appears to be associated with trailer wiring. I unplugged the two gray plugs, one of which had no gasket and both had considerable amount of moisture inside, to the point of dripping out of the connector interior. The RV is in my garage so I'm leaving them unplugged for now to dry out. So far it doesn't appear to have solved the problem although the phantom light is much brighter now.

Thanks for the info and pic. Where did you find the wet relays pictured. I see some of the familiar gray spray foam that looks like wet concrete so I assume under somewhere. After the post we returned from eating dinner to the parking lot to find all of the lights on the rear on. The only running lights not on where the original ones next to the headlights. This makes me even more think it is a control box on the Forrest river side and not Mercedes related. We drove 100 miles and now parked for the night at Walmart and I am back to a full strength led tail light making the bikes glow red! I am going to try to find those connectors in the morning. We have drove in light rain for the better part of 450 miles today. Thanks for the info.

[dukeboone]

I suppose it's possible yours is in a different location since you have a W and I have an S. Nevertheless the aluminum L bracket was mounted to the rear wall just left of the hitch receiver wiring harness. I've crawled under nearly the entire RV and this was the only relay and plug assembly I found.

[kysunseekermbs]

Thanks. I found it and my harness was in the exact same place. When I went out to check all my running lights were on with exception of the front again can again. I disconnected one of the connections that had either 4 or 6 wires and it turned all the running lights off. This allowed me to not be concerned as much about battery drain ect. and go to bed!

I totally understand how this is a water related issue, the harness is mounted on the backside of the bumper and gets direct road spray from the rear tires. The plastic connection has no seal at all. The dielectric grease is a great suggestion as I use that for outdoor landscape connections as well.

This forum is so helpful, I have a plastic crate of manuals that came with this, and although I have reviewed them all, there is little real world info or helpful info contained in them.

[dukeboone]

Update. Left both plug unplugged in heated garage overnight. Plugged in today and running lights all work. Left turn signal and left brake light do not. Need to wait for DW to test backup light. Tested each lead behind the light module and received what I think are accurate readings. The phantom left tail light is still on and I'm left to believe this is all related to the wiring harness and relay that I found. I've been in touch with my dealer who will be talking to FR and we'll talk again on Monday.

[kysunseekermbs]

Thanks for the update. I will be interested to hear the response. I am with mine for the week in FL on vacation. The last stop I had both tail lights on, one at 100% other at 20% brightness. Part of my routine now is to get under it and unplug wiring harness to shut it off when not driving. It has been dry for nearly 24 hours, will see how it goes tomorrow.

[kysunseekermbs]

Update / I am at the dealer I purchased it from while on vacation. I have been through service guy, 2 techs, sales mgr and back to service manager just to get them to look at it.

Service mgr just brought out a tech and they were discussing if mercedes problem or forest river. I told them everything works right in front end it does not appear to be a mercedes problem. They said there is a control box somewhere in the forest river side and they don't know where it is, would have to call forest river... That's where we are now. A summary of my problem is tail lights on when car is parked and keys out left right different levels of dim and bright. Brake lights don't work, turn signals don't work on rear.

I have had it for 6 days not a comforting feeling right now. We still have to go home when vacation is over at the end of this week without rear turn signals or brake lights.

[dukeboone]

Thanks for the update. I'd show them that plug that I had photographed. I personally think it's related to that. There's two plugs, a relay, a curt controller board and two other things on that plate. It appears to control the running lights, clearance lights signals and brake on the FR side.

[kysunseekermbs]

Another update - The sales mgr said forest river asked if it had the new led lights which is does. He said it could also be some timing relay problems in or behind the new tail lights. (Bad led tail lights) I get the impression they have had some issues with these already due to they asked if it had the new lights. He said electrical engineer is calling back soon with more info.

Regardless of what is causing this, it appears to be some type of controller like you have identified and not a hard wiring issue. I tested the brake lights a moment ago and they both came on but then stayed that way when I turned it off. They then when dim on own after a while.

[dukeboone]

For what it's worth, I removed the led lights and tested directly on a 12v battery and they both worked which makes me think it's relay related.

[JLeising]

Several related threads in the Solera forum. In our older Solera there is a circuit board with relays on it mounted behind a panel in the utilities compartment. I think FR changed a couple of years ago. While on older Soleras failure mode appeared to be no running lights, and seemed to preferentially effect units without LED tai lights or those pulling a toad, since the change "LED lights won't turn off" seems most common complaint. Reports are a board/module behind a panel in the water filter area. See this older thread:
http://www.forestriverforums.com/for...ion-80559.html

[dukeboone]

Originally Posted by JLeising

Several related threads in the Solera forum. In our older Solera there is a circuit board with relays on it mounted behind a panel in the utilities compartment. I think FR changed a couple of years ago. While on older Soleras failure mode appeared to be no running lights, and seemed to preferentially effect units without LED tai lights or those pulling a toad, since the change "LED lights won't turn off" seems most common complaint. Reports are a board/module behind a panel in the water filter area. See this older thread:
http://www.forestriverforums.com/for...ion-80559.html

Thank you for the additional info. I'm pretty convinced that's the issue and I'm awaiting a response from my dealer.

[kysunseekermbs]

The problem was the Curt tail light converter mounted on the back of the bumper. It states very clearly on the product info not to place it where it will get excessive moisture or water spray from tires. That's exactly where it is placed. I ordered the part off on Amazon for $21, changed it out and instantly fixed. I am going to install it permanently in a waterproof pvc box to avoid this problem in the future.

The problem started when I was near the dealer we purchased it from 5 days earlier. (Orlando RV) I had already researched on the forum and told them that this sounds like the problem. I was told by 3 service guys and the service manager that this could not be the problem and that I could bring it in a month from now and they could take a look at it. I was there for 2 hours and they said they were going to have forest river call me, which they never did. I had to drive 1000 miles home with no brake lights or turn signals, while having to manually unplug the lights each time we were parked as they would not turn off.

The dealer could of checked this in minutes by switching out from the one they had for sale on the lot and did not.. very frustrating.

For everyone that buys a RV from a local dealer just so they can get better service, don't. Just go for best price. Understand that you may need to become a RV expert very quickly and diagnose your own problems. On a side note, while I know it is not the case at all dealerships, the service techs I talked to, I would not want them touching mine anyway!

[Cfritts]

Well ours does this. Can you kick me the part number? Then I can figure it out from there.

[kysunseekermbs]

Sure Search on Amazon for the following

56146 Wiring Taillight Converter
by Curt Manufacturing

[Cfritts]

Thank you!

[dukeboone]

Originally Posted by kysunseekermbs

Sure Search on Amazon for the following

56146 Wiring Taillight Converter
by Curt Manufacturing

You'll also want the following:

MSD 8180 6-Pin Deutsch Connector
MSD 8181 4-Pin Deutsch Connector

[Cfritts]

thank you.

[MNtraveler]

Originally Posted by RedLdr1

Okay... Now swap it with the good right side tail light and see if the problem reappears. If it does reappear on the left side you have a controller module, or wiring, issue. That is a FR part by the way.. If it does not reappear on the left and the right side now acts up you most likely have a lamp assembly problem.

#8 was an absolutely smashing diagnostic recommendation. Odd how everyone went right by it.


Land of 10,000 Lakes
2016 Forester MBS 2401R

[RedLdr1]

Originally Posted by MNtraveler

#8 was an absolutely smashing diagnostic recommendation. Odd how everyone went right by it.

I tried... That is an old military troubleshooting technique I learned in microwave radio repair school in the early 70's.

[Pedrodasdas]

Hello All,

Just want to thank everybody involved in that thread. I just have the same problem here with my 2011 Solera (ghost light on right rear light).
Not sure if equiped with Curt converter, will check.

Pierre