Steve Aiken

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

Nuke

Putting a bandaid on a known, chronic issue is a bad idea and WILL leave you stranded soon enough.

The charging systems are known problems, even with replacement OE alternators. The fix is a PA Performance alternator (pricey but is worth not being left stranded).

Your radar detectors ability to detect a battery issue is non-existent. Voltage testing comparisons with the battery at rest with no load for the previous 12-24 hours vs. with the engine running might POSSIBLY lead to a CLUE that you have an issue but is also not a very good test.

If the battery IS healthy but just requires a good topping off (which even a healthy alternator is not the best at accomplishing), then don't wait for the battery to become degraded due to the alternator.

Chromeshadow

I agree with Nuke, it's prob the alternator. btw, to check the alternator it's best to measure voltage at the alternator and the battery, not a small wire to a radar detector.
The voltage should be tested with a load, you can turn your lights, fans, radio and everything else on to get close to the load used by the dealer. Voltage should stay above 13.6 VDC. I also check the current, but a DC current clamp is kinda pricy, mine was $600. Direct meters usually handle 20 A, trying to measure much more may damage them.
I'd check all of the connections and grounds all all of the large wires first. Any corrosion will magnify the problem of a weak alternator. btw, were the tests done in the car or was the battery and alternator removed for the tests?

CMcNam

Had the same issue. Replaced the alternator and the power wire with items from PA Performance. No problems since.

Rshustler1

I recently went through the same thing except mine started with the CEL for cam sensor then check charging system! First thing first go to your local autoparts store and buy one with a life time warranty. I originally got a pa performance witht the upgraded 50 wire. Nice product but it went out on me in less than 24 hours, called AM and the refunded me the alternator(great service) I decided to keep the upgraded wire because it was nice. Bought a local alt and it went out in a day then went to oreilys and bought one and I noticed the power wire had melted near the battery where it had apparently arced against the negative terminal.. Returned to original power wire and am still charging great with a local alternator that is lifetime guaranteed!

Moral of the story replace with lifetime warranty because it will go out again

mustangspotential

I had this same issue with the charging system and battery light coming on intermittently and eventually coming on for longer and longer after replacing my stereo with an aftermarket HU. After a month and a half, I replaced the alternator and nothing has been a problem since. The alternator was weak, but working enough to keep the car running even with accessories but would have eventually died. Better to replace it now then pay for towing when you're stranded and then get it replaced.

Steve Aiken

First off, thanks guys for the feedback. The dealer did a load test on the alternator output with all lights on. A/C etc and said the alternator was fine and that the voltage regulator was the problem. What I think I know is that the a rebuilt alternator can have a regulator that puts out too high a voltage and causes the problem, so I was told to go with a lifetime, brand friggin new alternator to cure problem. I don't have any add on electronics on board that need more juice so I plan to go with a local auto store with lifetime alternator and put it in myself, so about $200 and a few hours. We will see