Battery light is on on my 1995 f250 5.8 the truck has a gauge as well the gauge is running where it always has. their is no parasitic draw their was until I changed the alternator with a bad diode. The battery is a brand new interstate test at 12.65 when truck is running it shows 14.55 from alternator at battery. all engine compartment fuses receive voltage and have continuity. I recently changed the TPS and airflow regulator.

SOURCE: alternator light on

The alternator is not producing any power . If it were the engine would run without the battery. Check the wiring on the alternator. It must ave an exciter wire to make it work.

SOURCE: Electrical problem in motor home

yes you have a short and your on the right track.
with your test light in line telling you have a short we need to start removing fuses to fine the circuit that is the problem let us know what circuit and then we can help.
later paul

SOURCE: 1972 Ford F100 Alternator/Voltage Regulator wiring

Here is what you need.



Please rate this a fixya

SOURCE: speedometer, tack, fuel gauge, temp gauge have erattic behavior

With Ign. off what is your batt.voltage reading than take neg. cable off and take another reading 5 min. later. It sounds like a intermitten short, try to isolate voltage drop when acting up. Gauge circuit would be a good start. Schematic would be helpful.

SOURCE: 1989 Ford F250 7.3L Diesel. Bat light came on then smoked the VR

your alt and breaks are belt driven check your belts