We had a similar problem last Fall when traveling South to Yuma although our tow bar and auxiliary braking system, an Even Brake, are made by Roadmaster, not a Blue Ox. After arriving in Yuma and researching the problem, we found that the power wire within the coach plug was not connected to power at all. So, for several years we had been lucky that the pickup battery was strong enough that it had not discharged to the point that the pickup's engine would not start at the end of a day's towing. The Roadmaster Even Brake in the pickup is plugged into the cigarette lighter for operational power when towing.