Recently my daughters 2003 Windstar stopped charging. Runs fine as long as I've charged the battery up, but eventually it won't start or dies while running when the voltage is too low.

I've checked the output at the alternator- it does not exceed battery voltage. I checked all fuses, and they are all good. My understanding is that the center wire on the main alternator connector is a PWM signal to the regulator. I don't have a scope, but checking output on it with my cheap DVM shows a voltage change, so I'm guessing that there's a logic signal there. If I had to guess, I'd say that the brushes in the alternator, or the voltage regulator, are shot. So I'd like to replace the alternator.

My only concern is that there is no dash light indicating a battery or voltage issue. So, before I plunk down the cash for an alternator, is there anything else I should be checking? There are no Check Engine lights, alternator/battery lights, or anything else on to indicate a fault other than the symptoms previously mentioned.

Thanks for your time all. This is my first Ford since a 1997 Taurus that got rear ended right after the transmission started slipping.

 

You may have the correct info getting to the alt, but they have been known for having connection problems where the plug goes on to the alt.

 

Thanks for that Hanky. Is there a specific way to check for/resolve that?

 

All we did was to confirm the connections were clean and tight.

 

Thanks. I'll give that a shot. If I can't make any progress with that, then I'll order up a new alternator.

 

Hanky, I wanted to thank you for the help. Today I connected a voltmeter to the battery terminals, and fired up the motor. It was giving under 13 volts, and lowering, and I wiggled the alternator connector every which way but loose (pun intended) and it still didn't do anything. So, I decided to rev the engine just to see if that was all that was needed, and apparently after the wiggle jiggle, the voltage regulator kicked in around 3000rpm. After that, it started working normally. I'll be monitoring the voltages to make sure it stays charged after this, but it appears that the problem is solved, for now at least. I wonder if there's any trick for making sure the connection is a bit more solid.

Anyhow, you saved me $100. Thanks again for that!

 

It looks like I spoke too soon. Had to rescue my wife and daughter and a van full of groceries about 40 miles away from home the other day. It started charging after fiddling with it, then failed again the next day.

I bought an alternator on Amazon.com, new not rebuilt. Was only $85!! Here's the link if anybody needs one: http://amzn.to/2gvDDnB

I put it on today and it immediately charged properly. So glad to be done with that!