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Changed alternator, still have battery light

Contour_dave

New CEG'er
Joined
Oct 25, 2005
Messages
6
Location
Shawnee, Ks
Just changed out the alternator on the 2000 duratech. Battery light is still on after starting. Have had the battery checked and is OK. Anybody have any suggestions or advice? A little background, I had taken it to Autozone before changing the alternator and they said the old alternator was only putting out 4 amps.
 
Verify the following, on a FULLY CHARGED battery...

start the vehicle
test battery voltage while running.
13.7-14.2 VDC +- 0.1volts?

shut off car.. turn on headlights for 60 seconds.
battery voltage 12.0VDC or higher?

if the "running" voltage isn't enough, (like the same as the battery voltage) then check the "mega fuse". Its location can be found in the alternator how-to (duratec maintenance forum, in the "read first" thread.
 
OK, just pulled the megafuse and did a resistance test and it looks good to me. I'll get a new one to put in but am not real confident that this is going to fix it. BTW, the battery light came on when I started it one morning. No flickering, just a solid light.

If not the megafuse, not the alternator (OEM from a salvage yard), can I have the old alternator bench tested at Autozone or a mechanic?
 
Just replaced the megafuse, still have the battery light. When I went to get the fuse, I took the old alternator that I thought was bad and it bench tested good. So, it wasn't the alternator, wasn't the megafuse.

Also, did the voltage checks recommended in the post above. Had 12.7 volts at the battery when sitting, 12.04 volts when running. I'm stumped, know it wasn't the alternator, know it wasn't the megafuse, what next? HELP!!!!
 
Just replaced the megafuse, still have the battery light. When I went to get the fuse, I took the old alternator that I thought was bad and it bench tested good. So, it wasn't the alternator, wasn't the megafuse.

Also, did the voltage checks recommended in the post above. Had 12.7 volts at the battery when sitting, 12.04 volts when running. I'm stumped, know it wasn't the alternator, know it wasn't the megafuse, what next? HELP!!!!
There are only three things which can be wrong.

1) Alternator.
2) Wiring from alternator to battery
3) Megafuse

* 4) If it were an earlier model, I would say Fuse 5 (Fog lamps) is blown. Put a new fuse in just to humor me.

Edit. Did you test the battery per Ray's instructions? Headlamps on for one minute. Then check for voltage across battery terminals. If you did not, then maybe the battery is the culprit.
 
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Thanks so much for the help. There are several wires coming off of the alternator. I presume that if any one of them are bad in some way, then the alternator won't charge correctly? Any suggestion on which one to start with and trace? Which one goes from the alternator directly to the battery?

The fog lights are working so I presume that fuse is OK. I pulled the battery early on and had it tested. Tested good.
 
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then check the "mega fuse". Its location can be found in the alternator how-to (duratec maintenance forum, in the "read first" thread.

I am having the same troubles with my car and want to change out the mega fuse. I read the how to but can not find the part about the mega fuse. Can you help point me in the right direction?
 
Well, I just stumbled over the solution guys. On a 2000 duratech, there is an "alternator" fuse in the fuse box. So, I've replaced the alternator, no luck, replaced the megafuse, no luck, traced the wiring (as best as I could) between the alternator and the battery, no luck. The fog lights were working fine so didn't think it was that fuse as suggested but pulled the fuse anyway, looked good, no luck. Just happened to pull the fuse next to it while I was there, and it was blown. Looked at the reference and, low and behold, there was the description "alternator". So, spent countless hours changing crap out, a couple hundred dollars on tools and parts, and all it was was a freaking $3 fuse that nobody apparently knew about. Oh well.

I don't know if I'm happy or ticked off.

If anybody wants, I've got a OEM alternator I just pulled off that seems to be in perfect working condition that I would sell for $75 plus shipping.
 
Thank you for posting. That may save someone else from the same pain.

When I was a mechanic, it was my practice to check to see if I had power to the alternator before replacing it. I know it isn't easy to do so on a Contour V6, but it would have been easier than what you went through.

You may have still needed the alternator. There is usually a reason for a fuse to blow other than old age.
 
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