Most Popular Stop Light Switch for 2016 Smart fortwo

I did not order this item! It has only been suggested to me by an eTrailer employee in my quest to find the correct parts I need to tow my vehicle behind my motorhome! Your website suggested I purchase a "Stop Light Switch" for my vehicle but after I ordered it one eTrailer employee said I cannot use it in my vehicle as I have to disconnect the vehicle's battery. The picture of the RM-751437 shows a 7-pin plug but my motorhome has only a 3 pin plug! Do I need a 3-pin to 7-pin adapter? I also ordered the Roadmaster Invisibrake which was approved for my vehicle. Doesn't this run off or the car battery? I am no wiring expert and I also don't want to keep purchasing the wrong items (like the Stop Light Switch that I have to send back). I had ordered a Steering Stabilizer for my motorhome a couple of years ago and I got good advice on the exact part need and its installation. Why do I feel like I am on my own on ordering this towing equipment?

Kit for perfectly. A little challenging to hold bracket in place and get nuts to bolt to dash aligned and started. Helpful hint to remove obdII bracket to make it easier to bolt bracket in place, then reinstall afterward. Etrailer service was excellent to do business with!

This switch makes the braking movement turn on the light within our toad vehicle since our vehicle has a dead switch when in tow mode. So far it has been working fine just hard to see the tow display light maybe have to extend the display light to inside the coach dash.