My charging system is fixed

[dhewie]

I just wanted to pass along some info for people like me that are trying to fix a faulty charging system on a 2000 or similar Mountaineer. As I said in a couple other posts, I had accidentally drained my battery leaving the key on the other day. After a new battery, the charging light was near the L, and the battery light was on. After unsuccessfully finding anything with my limited knowledge of electrical, I took it to have the alternator tested while it was on the truck. They said the alternator was going bad only putting out 28 amps. I just had some nagging feeling telling me it wasn't the alternator even though people always blame the alternator. I have seen many posts on here talking about a fusible link. I ripped apart much of the wiring from the alternator and the battery cables with no luck of finding the link. But I did notice something that the positive battery cable and alternator cable hook to going into the distribution box labeled as 175A. The owners manual shows it, but makes no mention of what it is. After searching on Advance Auto's site for fuses, I found this part that I saw, and it was labeled as a 175 amp fuse. After more searching I found somewhere how to test a fuse, and then picked up one of these fuses on the way home just in case. Long story short, as a last ditch effort before shelling out $140 for a new alternator, I tested the old fuse, and sure enough it failed. Put in the new one, and good as new again.

 

[BrooklynBay]

Thanks for posting this information. Was that fuse the only one marked with a high amp (175) rating in that box? How many fuses are in that box?

 

[dhewie]

Actually, the reason I had trouble IDing it is because it's not in the box. If you look in the owners manual you will see in the fuse section for the distribution box, a 175A megafuse on the side of the box. The following thread shows this page, but the megafuse is cut off at the top of the picture: http://www.explorerforum.com/forums/showthread.php?t=180814&highlight=fuse+box+sticky
You actually have to flip open a top cover (lift up toward the middle of the engine compartment) next to the box to see the connections of the positive battery cable and alternator cable. The box cover actually has to be close or you can't see it. Those cables are actually bolted to the ends of the fuse. In between the two connections you will see plastic labeled 175A with the Ford logo and some other numbers. There was no indication it was blown, as it wasn't melted or anything. My only indication was that when I had the key turned on, the forward connection of the positive terminal was reading the battery voltage, but the other side to the alternator read nothing. So I found that you test the fuse by putting your volt meter leads on each end of the fuse and measure the ohms. It should read zero, if not, it's bad which is what mine read infinity or one depending on the ohm setting.

 

[BrooklynBay]

A low ohm range where the circuit of the electrical tester is closed is called continuity. I have an electrical tester which lights up, and beeps when it detects a closed circuit.