Motorhome Tow Plug Wiring Question

[Megsfolks]

I finished my Toad project and took a test run tonight. Everything works great... well, almost everything! It turns out my toad brake lights are not lighting with my motorhome.

My system is a Roadmaster Sterling tow bar with a BrakeBuddy Vantage Select. My Jeep lights are wired using the 4-pin connector supplied by Roadmaster to the rear Jeep lights through a Diode system installed by my local RV dealer.

Towing is great. BrakeBuddy Vantage Select is really cool and easy to use. No complaints. But, when I checked my lights, here is what I found.

The turn signal lights on the Jeep follow the turn signal lights on the motorhome. Great! The general lights on the Jeep turn on when the headlights are turned on the motorhome. So far so good! However, the brake lights on the Jeep don't turn on when the brakes of the motorhome are pushed. The brake lights on the Jeep DO turn on when the BrakeBuddy activates.

So, I've summarized/proven that all my bulbs are working fine and the diodes seem to be working.

So, I took my Voltmeter to the 7-pin connector on the motorhome. I checked the pins against those in the Fleetwood owners manual. Two of the four pins that are wired into the the Roadmaster 4-wire harness are denoted as Right Turn/Stop and Left Turn/Stop by the Fleetwood manual. I've confirmed that they are energized with the directional signals. However, they are NOT energized when the brake is applied; I can see the brake lights light up so I know that the Motorhome brake signal must be active somehow. Correspondingly, I do have a pin that Fleetwood denotes as "Electric Brake' that does energize when the brakes are applied.

So, isn't this a problem? Am I mis-interpretting that Right Turn/Stop & Left Turn/Stop should energize with either a brake or a directional signal? I can't imagine it to be proper or legal to tow the Jeep with only the toad brake lights lighting when the BrakeBuddy engages.

Is this a Fleetwood problem? Is it something easy to fix? Or, is this the way it is supposed to work?

[Megsfolks]

I finished my Toad project and took a test run tonight. Everything works great... well, almost everything! It turns out my toad brake lights are not lighting with my motorhome.

My system is a Roadmaster Sterling tow bar with a BrakeBuddy Vantage Select. My Jeep lights are wired using the 4-pin connector supplied by Roadmaster to the rear Jeep lights through a Diode system installed by my local RV dealer.

Towing is great. BrakeBuddy Vantage Select is really cool and easy to use. No complaints. But, when I checked my lights, here is what I found.

The turn signal lights on the Jeep follow the turn signal lights on the motorhome. Great! The general lights on the Jeep turn on when the headlights are turned on the motorhome. So far so good! However, the brake lights on the Jeep don't turn on when the brakes of the motorhome are pushed. The brake lights on the Jeep DO turn on when the BrakeBuddy activates.

So, I've summarized/proven that all my bulbs are working fine and the diodes seem to be working.

So, I took my Voltmeter to the 7-pin connector on the motorhome. I checked the pins against those in the Fleetwood owners manual. Two of the four pins that are wired into the the Roadmaster 4-wire harness are denoted as Right Turn/Stop and Left Turn/Stop by the Fleetwood manual. I've confirmed that they are energized with the directional signals. However, they are NOT energized when the brake is applied; I can see the brake lights light up so I know that the Motorhome brake signal must be active somehow. Correspondingly, I do have a pin that Fleetwood denotes as "Electric Brake' that does energize when the brakes are applied.

So, isn't this a problem? Am I mis-interpretting that Right Turn/Stop & Left Turn/Stop should energize with either a brake or a directional signal? I can't imagine it to be proper or legal to tow the Jeep with only the toad brake lights lighting when the BrakeBuddy engages.

Is this a Fleetwood problem? Is it something easy to fix? Or, is this the way it is supposed to work?

[RV Wizard]

Mike, you will have seperate fuses for the lights on the coach and the 7 way connector on the back of the coach. CHeck for a blown fuse for "towing brake light". Good luck and let us know what you find.

[teddyu]

Check with the dealer that installed the diode pack. I'll bet the diode pack prevents the TOAD electrical system from back powering the coach's brake lights when the Brake Buddy actuates. That's how mine works.

[Megsfolks]

Further testing shows NO brake light indication anywhere in the 7pin on the motorhome. What I thought was brake on, was 12V charging supply. So, I was hoping to find something that RVWizard pointed out.

RVWizard, I searched all three fuse boxes but nothing seems labeled as a fuse for the 7pin connector. On the Coach fuses, since nothing was marked, I ran continuity on them all and they passed. On the chassis fuses, nothing was marked as anything related to towing brake light or other indications. There was a Brake Light and it was fine.

TeddyU. I'm pretty sure you are right, and think this checks out ok if I understand.

[Gary RVRoamer]

You are correct that the Right & Left Turn/Stop circuits in the 7-pin connector should show 12v when the coach brake pedal is pressed. If they does not, something is wrong in the coach, either wiring or a fuse. If under warranty, you can ask a Fleetwood dealer to fix it. Otherwise you will just have to trace back until you find the problem.

[Renegades]

Mike,

One of the seven pins will have 12v on it when you step on the MH brake. Did the RV dealer who wired up the toad 4-wire connector add what looks like a square block with wires in and out?

You can not go from a 7-wire to 4-wire without this device. What it does is combines the brake signal to the turn signal wire. If you think about it, the running light and turn/brake lite on the jeep is a two filament bulb. With the turn/brake filament being the brightest. The diode pack that was added only allows for a separate input signal to the turn/brake light on the jeep. I have them on mine. If the RV dealer didn't add this combiner between the 7-wire to 4-wire adapter, it needs to be done.

I'll have to go dig up one up but from the gray cell area the 4-wire side should be as follows: white wire = ground, brown=running lights, yellow=left turn/brake, green=right turn/brake. I don't have the drawing with me to check it. There should be a pin on the 7-pin connector that will have the brake signal, when you step on the brake it will have power. Unless in the last 2 years they have added this, most RV manufactures do not put this on. They just provide the 7-pin connector on the back and it's up to who ever is making the connections to add the combiner.

I use to have these pre-made up so when an RV needed this done it took me less than 15 minutes to add it. Most RV dealers have kinda used the Uhaul standard wiring for the connector which is what I mentioned above. Thing to remember unless the RV manual says it's there then it isn't and you can not just put a 7-pin on one end and a 4-pin connector on the other end of a cable and expect it to work.

If you are still stuck, give me a call at 931-296-9709 and I'll try to walk you thru fixing it.

Jim - retired RV tech

[JerryForwood]

Do the brake lights on the MH light?
I had the same problem and found that when I connected the toad I had overloaded the brake switch and it blew. A new Brake light switch solved the problem.

[Joe and Pam]

I kind of had the same problem. Someone had installed a four to three wire adapter in the back of the motor home the problem was that it didn't need one because the turn/break were already combined. I cut out the adapter and everything worked as it should. You don't need the break wire if they are already combined.

[Megsfolks]

Well, looks like it was just a simple wiring problem as suggested by a few. Dealer installed the converter combiner thingy and now good to go!

Thanks for all the help!

[RV Wizard]

Anytime you mix a vehicle with all red rear lights and another vehicle with amber and red you will need a converter. There are tow different ones; a 3 to 2 and a 2 to 3. depending on which one has the ambers. Glad to hear you got it straightened out.