Left turn signal not working

[Overclocked]

I just went on a long trip & had no problems & my F150 did not flash any diagnostics related to the trailer. The F150 was correct with it's diagnostics.

It cost over $130 (2 lights, junction box + 8' 7-way electrical chord, diaelectric, & 7+4 prong hitch diagnostic plug). In the end, I have a clean & more reliable system than what Jayco provided at not much more cost.

But I also spent over 20-30 hrs troubleshooting from mid 2021 - June 2022.
Because many things that I did temporarily solved the problem until the camper moved.

But I saved 100's from not taking to Jayco & Ford Dealer. Plus they would have sent me to Ford to troubleshoot when my hitch diagnostic tester said the truck is fine + I tracked all the fuses on the F150 & all were good to go.

Suggest all wing nut junction boxes be replaced with the round wire connector junction boxes

[GL243]

I have the exact same problem with the exact same year and model trailer, almost the exact same truck (mine's a 2017), and, after reading your ordeal with great interest, and spending much of today muddling through my situation, I could use some advice.

My left turn signal is very faint, except for the furthest right two LED bulbs which are somewhat brighter, although still quite a bit less bright than the right turn signal. I get the "Trailer left turn signal" error message on the truck dashboard every time I turn it on. Brake light and emergency flasher function are also similar poor quality on the left side. Same as for you, it doesn't show any blinking at all when the turn signal is on when the running tail lights are on.

I cleaned the heck out of the truck and trailer 7 pin plug connector blades and slots with a little tooling file and alcohol, and applied di-electric grease to the blades, but that didn't resolve the problem.

I used a 12 volt test light and got good bright test light result when I checked left turn signal power from truck 7 pin receptacle left turn signal blade to the ground blade. After plugging the trailer plug back into the truck's receptacle, I got similar good test light result at the red wire coming in from the trailer plug wire bundle to the junction box behind the propane tanks (I grounded the test light to the trailer frame).

At one point, I turned on the left turn signal again and, surprisingly, there was no error message on the dash. The turn signal light worked perfectly for about 10 seconds, then went back to being very faint again. This had me believing the LED light panel itself was OK and that it must be a wire short issue somewhere else between the truck and the tail light.

My trailer has an enclosed underbelly. I detached the rearmost edge of that to see if I could find the wire bundle coming to the taillights but could not see any wiring accessible.

After finally figuring out how to remove the left tail light to get at the wires, I was able to also get good bright flashing test light result at the red wire that connects to the LED light panel, while the light panel itself was still blinking very faintly.

Questions - was the simple 12 volt test light I used adequate to conclude I was getting adequate power to the turn signal light, with no problems at the either the truck plug receptacle, the trailer plug connector, or the junction box? Is it correct to conclude that I need to replace the tail light as the next logical step? Or am I missing something else here?

Thanks for any help.

[ggilbert]

You could use a multi meter and test voltage at the trailer plug vs voltage at the light.

Also jayco used those stupid quick splice wire conductors. Those sometimes fail or installed so they cut most of the wire connectors you could eliminate those quick splice connectors and wire nut the wires together and test and see it the light is bright again.

I had to replace my light on drivers side. I used the light below and the heat shrink connection below.



TICONN 150 PCS Solder Seal Wire... https://www.amazon.com/dp/B07HCNTZ2Z...p_mob_ap_share

Command Electronics 9.5" Oval Red LED RV Trailer Camper Turn Brake Tail Lights License Light https://a.co/d/c4NrOpJ

[Overclocked]

What I found was that
1. The left turn signal light was faulty right from the dealer.
After replacing it & comparing both, connected & detached it was evident. Why would 1 work 100% (the new 1) & the original 1 not. And now for 100% of last season no problems.
2. I had a long ordeal over 2 summers as you could read of the left turn signal not working & then working for a short time and once all the way home from a 2.5 hr drive. Each time I had tightened the wire nuts in the junction box & always got different results. Once i moved the 7 pin connection from laying the slack from the left side to the right side & that's when it worked 2.5 hrs home. So....
3. I replaced the junction box & 7 pin wire harness simultaneously with item 1. The junction box is now the ring connection so no more wire nuts & wire slippage. If you go to a Jayco dealer as I did last year, you will notice that all of these campers now come with this style junction box.
4. It had made me think of just doing item 1 1st......but with everything so jammed in that tiny box & seeing how tightening the nuts affected the light performance at times & knowing there maybe an issue with the 7 pin chord, I did it all at once. The wire harness with junction box was ax. $40 on Amazon & a pair of lights with license plate holder $45 . Simple low cost fix.
5. The F150 has amazing diagnostics to to tell you it's not working. But it makes you focus on the connection, truck side, camper side, the 7 pin adapter & wire & then junction box. I now have a 2022 FX4 & the Jayco trailer is perfect. I recently attached a new Aluminum trailer I purchased & the truck gave me a similar light error code & issue was the adapter between trailer & truck.
6. It's surprising that I had this issue with a brand new Jayco & brand new F150 & tried 40 levels of troubleshooting. I hope it short cuts others experiencing the same thing. Just #1. Replace the light & purchase a pair to have a spare as it's not that much more for 2 vs. 1. If there's still a problem then change the junction box & wiring harness.

I hope that solves your problem & makes your day.

BR,
Overclocked from Appleton,Wisconsin

[GL243]

Thanks, gg and OC. I went ahead and ordered a new pair of Command lights per the link you provided. Hopefully, since I don't seem to have any issues yet with power making it from truck to tail light (there, I just jinxed it . . .), I won't need to get new 7-pin plug/harness or junction box, but thanks to your help, I know to do that next if the problem continues.

Based on my experience with getting warranty stuff fixed at the dealer, I can't even imagine how much it would have cost and the number of trips back and forth just to get one tail light working properly again. Wish me luck, thanks again for the help.

Regards

Gary

[Overclocked]

That's what we're here for. Can you imagine not having this forum or the internet to help share & solve problems. It would be frustrating & a long journey. Thanks to Jayco for this forum. .

The next step is to improve the quality of the campers.
I had:
1. This faulty left turn signal since day 1.
2. Short seals on the slide out
3. The passenger storage without the door latch
4. The main door �� hold connection on the door is upside-down. Instead of latching from the top down I have to latch the door from the bottom up.
5. The screen door was bent when closed it had a ½" gap at the bottom
6. My breaks never worked since day 1 & still don't work with 2 new trucks with integrated breaks. Lippert said maybe they were never broken in. But doing it at Jayco dealership 2x's & now traveling 3500 miles you think it would break in. I've disassembled & reset break gaps & cleaned breaks 2 times. No difference. My gain is 10 on both new trucks. I checked the wiring & put that junction box in thinking the connections were bad. No change.

[GL243]

Originally Posted by Overclocked

That's what we're here for. Can you imagine not having this forum or the internet to help share & solve problems. It would be frustrating & a long journey. Thanks to Jayco for this forum.

Absolutely. I've even managed to resolve a few issues the dealer had no clue how to fix (e.g., fridge not re-lighting in gas mode at higher altitudes - look up that thread on here if you ever need). The bliss of ignorance ends on a regular basis when you have an RV, and this as well as other forums have been my salvation.

[ggilbert]

if you don't already have some get some Butyl Rubber Caulk Tap. here the camper siding dips you may want to put a double piece. then trim the extra off after the light is attached.

https://a.co/d/e4zeXAb

[JFlightRisk]

Originally Posted by ggilbert

if you don't already have some get some Butyl Rubber Caulk Tap. here the camper siding dips you may want to put a double piece. then trim the extra off after the light is attached.

https://a.co/d/e4zeXAb

Good advice. I bought some butyl tape from Amazon many months ago for "just in case" repairs. Came in handy to replace our tail light when one of the license plate tabs broke off. I did put some layers on the low side of the aluminum to build it up, then tape on the light base before attaching it. Trimmed the top and sides, then put some Dicor non-sag caulk on it.

[GL243]

Thanks! I was thinking of asking what you guys used for the light fixture seal, so I guess you were reading my mind. Turns out I do have some of that.

[Overclocked]

I used a camper caulk