Alternator OEM FORD or OEM Volkswagen

The high rev voltage must be over 14 volts, so if not, then its the alternator. But make sure all connections clean and greased.

Eurovan exhibited similar behavior. Start and run fine until.... engine would lose power. Pull over and would die. Restart would be nothing. Sit for an hour or so and could restart and could get the few miles to home. Next day things could be normal or a repeat of slow down and die. This went on for a couple of weeks. The last fail found the battery to be toast even though only a year old. OK, so new battery. All good for the next few days then the gremlins return. New battery is now no good. Determined the alternator had developed enough play that when warm would start to short creating more heat and more of a short allowing it to eat the battery. New alternator and another new battery and all is and has been good.

At 48K miles I experienced an alternator fail (car was running great at the time).

check the charging at the battery while the car is running about 2000 or 2200 rpm with multimeter. The alternator should be charging at 14 volts (give or take a little)

Newer ford alternators essentially “talk” to the pcm. Cheap aftermarket alternators do not do well on these cars. Replace the alternator with a better quality alternator

Mine has 69K miles. I've owned it for 4 years. Replaced the alternator and MAF sensor after failures. Keyless entry works only sporadically on the driver's door (lock switch already replaced - latch mechanism needs to be replaced, but for $$$).

My neighbor had a Ford mustang and he had to jump start it about once a week. I checked the alternator and it had power when the car was off. Bad diode.

I have a shitty looking Ford Focus that I maintain myself...The alternator failed and I couldn't be bothered doing the work myself so I took it to the local dealer.

What bugs me now is that it seems the alt doesn't quite put out. Dash light (at least the one I put under the dash since the one in-dash quit working) won't go out. Goes from bright to dim when the alt should excite.

I haven't had this problem with my RX8, but I had a similar problem with my Ford. Alternator was putting out 14.4V, but I still had a light. Took it to the parts store and they hooked it up to their tester. It said the Alternator was no good.