2005 Sport Trac Battery light flashing and on steady at times

[madamo395]

A week ago while driving my am/fm radio crapper out complevery. All gauges went flat, speedometer, gas, temp etc. I got to my driveway and knew when I shut it off it would be dead. Sure enough, wouldn't start again. Volt tester had the battery at 11 volts. I replaced the battery, vehicle started right back up. Volt tester while running had new battery at 14+ volts. Vehicle then sat for a week while I went on vacation. I came back and vehicle started right up and is running fine. Know the battery light is blinking and sometimes stays on steady for an extended period. Think maybe there is a short somewhere. Where do I start? Is this a major problem? Please help.

 

[RandomNerd2000]

That sounds like an alternator problem to me, the battery light is related to a wire coming off the alt.

 

[SoCal2V]

Doublecheck all connections at the battery (incl. chassis grounds to radiator support) and alternator that they are clean and secure, but other than that I'm with the above post that it's probably new alternator time.

I had a similar issue with a flickering battery light on my Mustang a couple years ago - although no charging issues. The shaft bearings on the alternator were worn and allowing excessive shaft endplay, on the car it spun just fine but when I removed it and set it on the ground with the pulley facing upward it felt like the alt was full of sand. That endplay allowed the windings to be out of alignment with whatever other magical components in the alt and thus led to the light coming on.

 

[koda2000]

You don't have a short, but you may have a bad connection at the alternator.

 

[94stockexpl]

Having a similar problem, may need to start a new thread but here is my issue.
Saturday, I went to start my 05 Sport-Trac and it just clicked, this after starting and driving it all over through the day. Called a buddy, jumped it and off I went. 2 miles down the road the dash gauges, radio, power windows, AC all went dead and the ABS and airbag warning lights came on. Pulled into OReilly and had them check battery- was at 7.5 volts. So I recalled the same thing happening with it about 7 years ago and the alternator turned out to be the culprit, so I got a reman alternator, and changed it out while they charged the battery. Everything good for about 10 miles, then the battery warning light came on and all gauges dead. This happened about 8 times over 25 miles Got home, then this morning (Sunday) it was so dead the interior lights didnt coem on. Slapped charger on it and 3 hours later it started up.
So voltages that I checked were as follows: Not running 11.54 V on battery, voltage when running 11.33 V. Then later after charging it some more, the running voltage between the alternator and the neg battery post was 14.4, certainly in range. Went on some errands and now notice that everytime I accelerate from a stop or very slow roll, the dash goes dead and battery light on. Then if I slow down to idle or stop, it all comes back on. SO, connected my voltmeter to the alternator and neg battery post with long jumpers so I could see what it did while driving, and when the dash went dead, the voltage jumped to 17.4 to 17.8, then dropped as I slowed down. Whenit got down to about 15 volts, the dash come back up

The 17 + volts makes me think voltage regulator, but would it be tied so directly to engine RPM?

Any assistance or ideas welcome
John

 

[madamo395]

This morning on the way to work, radio cut in and out, ABS light came on and just battery gauge went all the way to L. It was still dark this morning. I shut the radio, shut the headlights and drove another 13miles to work. After work, I change the alternator. I'm no mechanic and it took under 30mins. Battery light is off and running good. I got home and volt meter reads 14 while running and 12.93 when off. I got my fingers crossed it's fixed. Thanks for the help guys.

 

[koda2000]

Sounds like you got an alternator with a bad voltage regulator. Anytime the BATTERY light is on the alternator is not charging the battery and the vehicle is running off the battery, which depending on electrical use and condition of the battery can keep you running for quite a few miles. The fact that you saw 17.8 volts at one point also points to a bad VR.