John and others, Current Ford vehicles (since 1986) are dependent on the in dash bulb to charge. Early models had a 500 ohm resister in parallel with the bulb and placed in the twist in type bulb holder. if they fell out or made poor contact, the alternator couldn't charge. It was the devil to fix if you didn't think (or know) to look at the battery symbol on the dash as part of diag. What about finding a suitable resistor for the D and soldiering it in parallel with the bulb on the printed circuit (like recent Fords)? Don