acme15

In the end I rewired it. New positive, new earth, new switched live feed, new fuse, new relay, and spliced it into the wire corresponding to the alternator middle wire. Working fine now.

OK so at idle the alternator is putting out about 11.5V. I measured this voltage from the positive output on the alternator to the casing of the alternator with the engine running. So my attention then turned to the loom pigtail with its three wires. The two outer wires have continuity to ground and 12v with ignition on, but the middle (black and red) wire has neither. The middle wire is switched ignition. The 7.5A switched alternator fuse is fine. So I'm assuming that is my issue. I need to know where that red and black wire goes after it disappears off into the loom. On some cars it is yellow and black. Help?? 🙂

Need a hand please! '98 UCF20. It is a Toyota Celsior but that shouldn't make a difference. Car died, battery wasn't getting any charge. Putting a new freshly charged battery on resulted in the battery quickly discharging. I therefore diagnosed as a dead alternator. Alternator and its connectors were covered in oil from a leaky valve cover gasket. Alternator and gasket both replaced, and connectors cleaned with contact cleaner. The car now works and the alternator is maintaining the battery voltage, but it only sits at around 11 volts. I can drive along with AC, heated seats, all lights, etc, and it regulates to 11 volts. When I switch the car off, the battery voltage slowly recovers to over 12 volts again. I have tried a known good battery - Two in fact! Tomorrow I am going to check the output at the alternator. My questions are: a.) If the alternator is outputting 11V instead of 14V, is there anything other than the alternator which can cause this, given that it is a new unit, and the regulator is built in? b.) If the alternator is outputting 14V - What could be causing that voltage loss between the alternator and the battery? A short or bad ground etc? Are there common places for this to occur? Many thanks!