ABS light, flickering ABS light, not charging

GPOWE

MEMBER
2001 FORD EXPLORER
4.0L
V6
4WD
AUTOMATIC
225,000 MILES

One day my ABS lights came on then the battery light turned on a few minutes later. Soon I lost power and I turned the truck off. The battery was dead. I received a jump and it instantly started, so I drove to Auto Zone to have it tested. They tested and it failed so I purchased a new battery. With the new battery in, the voltage meter was low, but it ran with no issue for 2 days. Then the battery light began to flicker when the RPM was in idle, but stopped when I accelerated. 3 days later, the ABS light came back on and the battery light as well. I turned the truck off and it would not start or roll the windows up. Turned ignition off, then back to the on position and it gave me enough power to roll the windows up. The battery terminals were a little corroded, but I had them cleaned before the new battery. Any suggestions?

1 Reply

CARADIODOC

MECHANIC
33,867 POSTS

The "Battery" light means the battery isn't being recharged while you're driving. It's the charging system you need to have tested, not the battery. If the generator is totally dead, you'll be able to drive no more than an hour after charging the battery fully, and even less if the heater fan, radio, head lights, or other things are turned on.

When you're able to drive for a day or two, or even a couple of weeks before the battery runs down, it's likely one of the six diodes in the generator is bad. That will reduce its maximum current capacity to exactly one third of its rating. 30 amps from the common 90 amp generator is not enough to run the entire electrical system under all conditions. The battery has to make up the difference until it runs down.

You need a professional load tester to test for full-load output current and "ripple" voltage. If rippIe voltage is high and maximum output current is low, a diode has failed. It really isn't practical to replace a set of diodes. The generator is replaced instead.