I have a 2003 Ford Windstar that has an electrical problem. When I first bought it sometimes the reverse tail lights would come on while I was driving down the road or when I parked. The dealership could not find the cause and it went away for 5 years. Last year the ABS and Brake light came on and stayed though the mechanic said the brakes are fine. Now the “short” is in the dash. Sometimes when the ignition is turned it just clicks like the starter is bad, won’t start and the headlights flash on. When it does start it is sluggish like the battery is weak but finally turns over. Sometimes the radio and odometer lights flicker on and off. Sometimes the radio works but only picks up engine interference, not stations. When the van accelerates the sound goes up in pitch. Even though it is turned off, the windshield wipers will swipe sometimes. Once the electric window on the passenger side made engine interference noise like the radio when the button was pushed. Once the seatbelt alarm went off even though we were all snapped in. Once all the needles on the dial went all the way to the right, then left,right, left, even though the engine was running smoothly at an even 55 mph. None of this happens all the time, or all at once. The radio and odometer seemed to be connected. The wiper swipes by itself. Sometimes the engine runs rough when the odometer and radio are acting up. The van has 126,000 country miles and has been maintained. I’d like to keep it but these problems are weirding me out. The starter was changed without affecting these symptoms. Any suggestions?
Have the alternator checked for AC ripple at the battery while the engine is reving around 2,000 RPM. If there is over 0.1 volts of AC ripple measured replace the alternator. Also have the battery load tested to check it’s condition.