Towed vehicle turn signal not blinking when connected to MH in Tow Mode

[Scobysisters]

2015 Newmar Ventana - been towing an F150 for 2 years now without issues, until now. When truck is in Tow Mode and connected to MH, the right (passenger) rear light does not blink. This is the ONLY situation in which this happens. After several calls to various techs and some trouble-shooting, we are STUMPED! We've already ruled out the Tow Flasher Relay and the Tow RH Fuse in the MH, and the "umbilical cord" (7-pin to 6-pin). We've ruled out any issues with the Truck, because all lights/flashers work fine when in Tow Mode NOT connected to MH, and also works fine NOT in Tow Mode.
The Break Lights, Left Turn Signal and Hazzard lights all work fine when truck is in Tow Mode and connected to MH. It's JUST the right rear blinker of the Truck (towed vehicle) that Does NOT Blink when in Tow Mode and connected to MH - it just lights up and STAYS SOLID.
ANY IDEAS before we pay a ton of $$ to Freightliner??

 

[Scobysisters]

2015 Newmar Ventana - been towing an F150 for 2 years now without issues, until now. When truck is in Tow Mode and connected to MH, the right (passenger) rear light does not blink. This is the ONLY situation in which this happens. After several calls to various techs and some trouble-shooting, we are STUMPED! We've already ruled out the Tow Flasher Relay and the Tow RH Fuse in the MH, and the "umbilical cord" (7-pin to 6-pin). We've ruled out any issues with the Truck, because all lights/flashers work fine when in Tow Mode NOT connected to MH, and also works fine NOT in Tow Mode.
The Break Lights, Left Turn Signal and Hazzard lights all work fine when truck is in Tow Mode and connected to MH. It's JUST the right rear blinker of the Truck (towed vehicle) that Does NOT Blink when in Tow Mode and connected to MH - it just lights up and STAYS SOLID.
ANY IDEAS before we pay a ton of $$ to Freightliner??

 

[John&Andrea]

Look at the connection at the light that is not working. There is something that connects the towed lights to the MH. Possibly a diode kit was installed.

 

[Rollin Ollen]

2015 Newmar Ventana - been towing an F150 for 2 years now without issues, until now. When truck is in Tow Mode and connected to MH, the right (passenger) rear light does not blink. This is the ONLY situation in which this happens. After several calls to various techs and some trouble-shooting, we are STUMPED! We've already ruled out the Tow Flasher Relay and the Tow RH Fuse in the MH, and the "umbilical cord" (7-pin to 6-pin). We've ruled out any issues with the Truck, because all lights/flashers work fine when in Tow Mode NOT connected to MH, and also works fine NOT in Tow Mode.
The Break Lights, Left Turn Signal and Hazzard lights all work fine when truck is in Tow Mode and connected to MH. It's JUST the right rear blinker of the Truck (towed vehicle) that Does NOT Blink when in Tow Mode and connected to MH - it just lights up and STAYS SOLID.
ANY IDEAS before we pay a ton of $$ to Freightliner??

I doubt it's a Freightliner issue. I had a similar problem happen to out 2018 JK. Turned out to be a broken wire on the Tow Wiring Harness. It's odd that everything works fine except in tow mode though. It still sounds to me like you have a trailer wiring harness issue. Check that first and cross your fingers.

Darrell

 

[Diesel Pusher]

Sounds like dirty connctions. Did you clean the 7/6 pin connections and pin sockets on the cable?

 

[rvkev]

Clean your connector(s), by blowing out with compressed air. Try some electrical contact cleaner. I use JB 80. https://www.lubesuppliers.com/products/jb-80-spray-lube-13-oz]Justice Brothers 80[/url].

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If you have two flashers, switch the flashers?

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Possible ground back feeding when in tow mode. Does it make a difference when in tow mode and connector is hooked up, but the hitch is not connected?

 

[Scobysisters]

Clean your connector(s), by blowing out with compressed air. Try some electrical contact cleaner. I use JB 80. https://www.lubesuppliers.com/products/jb-80-spray-lube-13-oz]Justice Brothers 80[/url].

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If you have two flashers, switch the flashers?

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Possible ground back feeding when in tow mode. Does it make a difference when in tow mode and connector is hooked up, but the hitch is not connected?

We had just cleaned the connectors and this didn’t help. What do you mean by “connector is hooked up, but the hitch is not connected?” Which “connector” are you referring to? The blinker works when toad is in Tow mode and NOT connected to MH.

 

[Scobysisters]

Clean your connector(s), by blowing out with compressed air. Try some electrical contact cleaner. I use JB 80. https://www.lubesuppliers.com/products/jb-80-spray-lube-13-oz]Justice Brothers 80[/url].

---

If you have two flashers, switch the flashers?

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Possible ground back feeding when in tow mode. Does it make a difference when in tow mode and connector is hooked up, but the hitch is not connected?

By “flasher” do you mean the light bulbs on the toad that flash? Forgive me for my ignorance, but understanding electrical/auto is challenging to me.

 

[Scobysisters]

Look at the connection at the light that is not working. There is something that connects the towed lights to the MH. Possibly a diode kit was installed.

What is a diode kit? And where is this located? Somewhere on the toad?

 

[Scobysisters]

I doubt it's a Freightliner issue. I had a similar problem happen to out 2018 JK. Turned out to be a broken wire on the Tow Wiring Harness. It's odd that everything works fine except in tow mode though. It still sounds to me like you have a trailer wiring harness issue. Check that first and cross your fingers.

Darrell

Where is the Tow Wiring Harness? Is this behind the 6-pin connector on the toad? Or at the MH end? Is this something we can get to? Or is this something an electrician/tech should do? And if so, an RV tech or a trailer tech, or a Blue Ox tech? Who would know more about this issue? We’ve asked RV techs and they said it may be the Tow Relay on the MH - it’s not because we replaced that relay. It’s also not the fuse. Thanks for your reply.