redfishbluefish Posted May 13, 2021 Report Share Posted May 13, 2021 We have a 2010 Edge Limited that has been pretty reliable for the last 86K or so miles. Last weekend, while seeing family a few hours away, the charging system light (battery icon) came on while running a short errand. Hoping it was a fluke, I drove the the following morning. Charging system light comes on, ABS light and check brake system warning comes on a few minutes later but the car is still running fine. However, once I turned it off, it wouldn't start - just clicks. I jumped it with another vehicle and it started and ran smoothly (with the same warning lights on). Because it seemed that the alternator was powering the car and the battery was about 5 years old, I pulled the battery and bought a new DieHard. Started it up, and the charging system light comes on. Perhaps unwisely, I start the 120 mile drive home. After about 50 miles, ABS and brake system lights come on but the car runs fine for the rest of the drive. Turn off the car at home, but it won't restart - just clicks. Now that I have my multi-meter and YouTube, I start testing. Alternator and PCM fuses are intact. Battery posts and connections are clean and tight. My cheap CAN-ODB scanner shows no faults. I charge the brand new battery overnight. The battery itself was about 13.2V but once I start the car, it drops to about 12.6 or so with the charging system light on. Clearly, the alternator is NOT charging the battery. Adding in some electrical load (fan, lights, radio) brings it down to 12.0. The alternator is turning, not making any odd noises, and the belt seems tight with no slipping. I tried a few voltage leak tests on the neutral side and It was about .19 from the alternator with electrical load an at 2000 rpm (Now, I am NOT positive of this .19 figure due to my cheap multi-meter and the difficult alternator location). After much online digging, I am wondering if it is a connection from the alternator to the battery or possibly the voltage regulator in the alternator. Do dying alternators sometimes produce enough power to run the car but not provide any charge to the battery? I am not opposed to just having the alternator replaced except I know that labor will be a bear since it appears they need to move and remove all kinds of things to get in there. Quote Link to comment Share on other sites More sharing options...
WWWPerfA_ZN0W Posted May 13, 2021 Report Share Posted May 13, 2021 (edited) https://www.youtube.com/c/MACTFordEdge/search?query=alternator all signs point to alternator failure. if it were charging the battery in your 2010, voltage should get up as high as 14.5-14.6 with the engine running, at least in the first few minutes from a cold start. use a device like a solar ba9 to check alternator function (the MACT effort gets a kickback from this link) https://amzn.to/2RPEGfY and/or use an amp meter to see how much current is actually flowing from the alternator to the battery. it has hardly ever been wiring related, but if there are pest issues in your area, it is a possibility. if terminals are not tightly attached, that is another possible scenario. buy a motorcraftalternator whenever possible, especially if you dont want a redo of the install. Edited May 13, 2021 by WWWPerfA_ZN0W Quote Link to comment Share on other sites More sharing options...
redfishbluefish Posted May 14, 2021 Author Report Share Posted May 14, 2021 Great feedback! I did go to Advance Auto yesterday and we ran the alternator test on their equipment. As suspected, there was no sign of current flowing to the battery. But that begs the question - if the alternator has failed, then what kept the car running for two hours after the battery drained? Are there separate outputs from the alternator - one to charge the battery and one to deliver power to the other systems? Quote Link to comment Share on other sites More sharing options...
WWWPerfA_ZN0W Posted May 14, 2021 Report Share Posted May 14, 2021 unless you have a high amp stereo system or similarly power hungry equipment, most of the electrical needs are at startup. once the vehicle has started and electronics have stabilized, headlamps and engine fans are usually the most power hungry appliances. on a highway drive, it is unlikely engine fans were needed. and unless you were driving in darkish conditions, or have DRLs on, the headlamps would not come into play. that is my best guess. Quote Link to comment Share on other sites More sharing options...
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