98 ford explorer battery

[djones55]

the battery has been going down used a test light to find the fuse and it was the alternator system fuse under the hood. can anyone tell me what it does and how can i fix it so it stops draining the battery thanks

 

[J_C]

Odds are that your alternator has a failed, leaky diode in it and needs replaced or rebuilt. You can do a check with a multimeter by disconnecting the thick battery cable to it and measuring for current between the cable and the alternator lug, with the alternator fuse back in place. With the engine off there should be extremely close to zero current (microamps at most), while enough of a drain to notice would at least be several milliamps.

Otherwise some autoparts places have an alternator tester, but as far as I know this is a test where you must take the alternator out. The tester can't be brought to the alternator still in the engine.

 

[BrooklynBay]

You could check the charging system with a multimeter. What is the voltage with the engine running compared to the engine off?

 

[djones55]

thanks for the help i will try it and see what happens thanks again