We were driving toward Carbondale, Ill when the “Do Not Shift” light came on again. My first thought was that something had gone wrong with the transmission repair done just a few days ago – the new “output shaft speed sensor” had failed, or the plug connecting it to the wiring harness had come undone. We kept going while Dinah researched the nearest transmission repair place.
But then the speedometer became erratic and pegged at 80MPH while the GPS said we were doing less than 60. When the tachometer started to fail and we began to loose power we decided it was time to get off the road. We turned onto a side street and headed for a deserted gas station. About 200 feet from the gas station, the engine quit and it slowly dawned on me that this was more than a transmission problem. For the first time I checked the dashboard voltmeter. It showed that the vehicle battery voltage was below 8 volts.
Our RV has 2 separate sets of batteries: the “vehicle” batteries which handle the starter, engine, headlights, etc, and the “house” batteries which operate the inside lights, refrigerator, and, through the inverter, the TVs, microwave, and other 110v stuff. There is a dashboard switch that connects the two systems together, and by using that switch I was able to get the engine started again, and get us off the road.
I knew the vehicle batteries were old, and had been drained and left discharged for months when we left the RV in storage in 2006. I assumed they had died and started to collect the measurements and specs I would need to replace them when it dawned on me that the symptoms pointed to a charging problem, not a battery problem. If I tied the 2 electrical systems together and used the 110v generator to charge the house batteries, we would be in business! Rather than holding the momentary contact dashboard switch to connect the two systems while I drove, I rigged a jumper on the relay that the switch controls, watched the vehicle battery voltage slowly climb, and we were on our way. There was nothing wrong with the transmission – it was just reacting to the low voltage.
We spent the night in a campground in Poplar Bluff, MO with an appointment at the local truck repair place for this morning. They quickly diagnosed a bad alternator and replaced it. Two hours and five hundred dollars later we were on our way.
We have been very fortunate in that none of the problems we have had with our motor home over the years have required that we be towed – we have always been able to get to a repair facility under our own power. We are hoping that our good luck will continue.