Steve Aiken

Help please
I have a '05 GT Mustang. This warning and the buzzer noise have been coming on and off for months. The car runs and starts without any hesitation every day plus I monitor the car voltage with my radar detector constantly and the voltage levels are fine all of the time.
A new alternator was installed less than two years and new battery fairly recently. I had an auto parts store do a battery/alternator load tests after this warning kept coming on and their tests indicated all is fine.
I had it in the dealership for other things yesterday and added this problem to the list. Their diagnosis is weak alternator. I am beyond the warranty period for the recently replaced alternator. I chose to live with the problem for now since I don't believe the alternator is bad.
However the buzzer noise is un-nerving and the warning bugs me.
Where is the freaking buzzer located and how do I shut it up?
Any other good ideas? Some relay somewhere causing problems
Help
Steve

go-part

Have you checked over all of the grounds?

Su Roberts

I also have the same problem with my 05 every morning I get a check engine charging system. No change in battery drainage gauges are all ok this goes on & off about 3 times then it doesn't come back on for the rest of the day. Doesn't shoe signs of draining or change in performance. New alternator New battery. I have even gone through the steps of making sure Alpine is shutting down. It's a mystery to me but if you find out how to turn off buzzer I would also like to know.

Derf00

Ford (and most dealerships) have charging system testers that do more than just check voltage or amperage. I forget what the system is called but a diagnostic on one of their pieces of equipment takes about 3-4 hours...that's actual run time once the equipment is hooked up, not just putzin around looking at things or taking a break.

Anyways, if the dealer tested it with that equipment, then you are pretty much assured the problem they found is the source....bad (weak) alt in this case.

Auto parts stores are hit/miss. Their bench and "on car" testing just do a voltage test and a quick load test (amperage). It doesn't test diodes or regulators, or grounds, etc.

Two cases in point.
1) Old 2000 V6 mustang I had started to get the Battery light ot flicker on WOT. Took the alt off the car had it bench tested. 3 out of 5 tests showed it as good. I went ahead and replaced the alt anyway. Zero problems afterwards.

2) My 08 recently had a bad battery...but it was a bad cell in the battery. Car had to be jumped to start. Drove it to Autozone, they tested it in the car, it tested fine and the car started right up. Let the car sit for 30 minutes, they tested it again...wouldn't even register on their tester. Replaced the battery, no more problems.

mustang country

The same thing happened to me last year. I drove around with the "Check Charging system" light thinking it was a computer glitch. When I took it to the dealership, I found out that it was a bad alternator. The reason I thought it was a glitch was because I took it to an auto parts store and they did a voltage test. They told me everything was fine. I think the best thing to do is take it to the dealership. They can perform various tests that local and other auto parts garages can't do.

Steve Aiken

Of course the dealer told me I needed another alternator also, no problem just $600 plus. I had just had one put in 1 and a half years ago but of course it is now out of warranty. I am convinced that the problem is actually over voltage charging meaning the voltage regulator Is not "clipping" off the voltage peaks properly. The solution is a new alternator which will have a new voltage regulator. Ford apparently puts in refurbished alternators when they do repairs and I think I got one of them. My intended solution is to put in a new, spelled NEW alternator from a local auto store with full life warranty. In the mean time I continue to listen to the damn warning chime ever time I drive. The wrenching required to put in a new one is minimal but I have not got to it.

Steve Aiken

Final part of this story is that I did install a NEW alternator with a lifetime warranty from Advanced Auto parts. It FIXED the problem. No more trouble alerts or chimes. The car voltage monitor (radar detector) never reads more than 14 volts and is much more stable than before. The installation was easy, assuming you have a good of tools, in particular a break over bar with 1/2 drive for relieving belt tension, deep reach metric sockets, and metric open end wrenches. YouTube videos were helpful and a confidence builder.

Derf00

Good to hear the new alt fixed your problem. I tend to trust the dealerships troubleshooting skills on stuff like that since they have better equipment for FORD specifically but then I use that diagnosis to actually fix it myself and save the coin.