Battery Warning Light

Have 97 4 Runner with 212,000 miles. The Battery Warning light is on much of the time? Voltage at battery under idle seems high at 15.8 volts. When loaded down with lights and fan motor the charge voltage drops to 14.4 volts. Car seems to run fine and start ok. Warning light will go out for short period of time when driving down the road. Suggestions anybody?

Have your charging system checked - sounds like your voltage regulator is bad.

http://www.automotiveforums.com/vbulletin/showthread.php?t=166525

Have your charging system checked - sounds like your voltage regulator is bad.

http://www.automotiveforums.com/vbulletin/showthread.php?t=166525


Is the voltage regulator part of the alternator? If so would I be better off buying a rebuilt from an auto part store? With 212k miles I would think I am on bored time with it anyway?

Yes, the voltage regulator is in the alternator. I would have the alternator tested before I bought one.

Yes, the voltage regulator is in the alternator. I would have the alternator tested before I bought one.

Had the Alternator tested and the report came back it was bad. They said output current very low. Since then I replaced alternator with new/Rebuilt unit. Seems to work well...except the battery warning light stays on all the time! I am confused as to how and why this warning light is on. ideas??????????

What's your alternator output voltage now with the new alternator?

What's your alternator output voltage now with the new alternator?

Output voltage looks good at 14.8 volts. Probably not a wise test but I disconnected the battery with engine running with lights, fans, and anything else all turned on and the voltage remained right around 14 plus telling me the current capability of the aletantor was good. Looking at the schematic of what I have makes no sense on how that light could be on. With the old alternator if at least would go off on occasion where now it is on regardless. I am guessing the new alternator sensing circuit may be at fault? Clueless here.

how's the battery? might not be holding charge well or cables might be rough

how's the battery? might not be holding charge well or cables might be rough

Mystery solved. Tried second new alternator with same results...Battery warning still on. Bought Chilton's manual and after studing it a bit decided to check voltage at the alternator. 12 volts was missing on one of the pins. Trace it down and determine there was an open in the wiring harness between the alternator and the fuse box. Replaced wire and problem solved. All is good. Thanks to all for your time. GB

Good job!