My ford explorer sport truck battery will not stay charged we know it could b the alternator we are wanting to check the fuse first but no owners manual to say where the fuse is located can u tell me whereit is located?
It used to be a 15 amp fuse in the under-hood fuse box. Measure the voltages at the plug on the generator. If the wire colors are the same as they used in the mid '90s, the yellow wire should have battery voltage all the time unless that fuse is blown. If the battery light turns on, the green / red wire is working. You should find about 2.0 volts on it. If you find 0 volts, that wire is shorted to ground. The light will stay on and the generator will not turn on. If the battery light never turns on and there's 0 volts on the green / red wire, that wire is broken. If there's battery voltage on that wire, either the terminal is not making a good connection in the connector or the voltage regulator is defective.
If the voltages check good, look at the six screws on the regulator. Four of them hold it to the back of the generator. The other two are connected to the two brushes. One might have a protective plastic cap on it if it hasn't fallen off yet. Measure the voltages on those two screws while the engine is running and let me know what you find.
February, 26, 2011 AT 5:36 AM
Caradiodoc has great ideas but watch out as roughly around this time frame, Ford changed from a conventional Alternator system to one that uses the engine computer to regulate the alternator and requires a scan tool to properly diagnose