I have a 97 F150 4.6L 4WD and for about the last two weeks the charging system has seemed to have a mind of its own and has been very intermittent. The first thing that happened was as I driving down the road the entire truck shut down, and by that I mean the engine and every bit of electronics inside the truck, and then it came back on within a few seconds. I made it down the road another mile or two and it did the same thing except this time it took about five minutes before everything came back on and I was able to start my truck. Once it started I noticed that the voltage gauge was only reading about 10V and was dropping so I took it to a mechanic where they replaced my alternator and all was well for about a week. Then I noticed that my headlights and my heater fan in the truck would dim out for a few seconds periodically but I didn't think much about it until one morning the other day when I went to leave my house and the voltage gauge was down around 9V again with the truck running. I did some checking and found that my ground cable on my battery was not making a good connection and replaced that and tested the alternator with a multimeter on the battery with the truck running and had 14V. Today everything seemed to be fine as I was driving around and then once again I noticed that I was getting a low charge again so when I got home I tested at the battery again and was only getting a little over 9V. I went inside for about an hour and then came back to do some more checking on the truck and for no apparent reason was back to charging at about 13.6V but I did notice that as the truck sat idling the charge was dropping very slowly and dropped down to around 11V. At this point I don't know where to look next. Any help would be much appreciated.
Jan 17, 2010 at 11:00 PM