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#1604956 07/06/06 10:31 PM
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I have been having charging problems with the alternator to battery wiring. I pulled the coil pack out and the mega fuse is hanging there, now I took my multimeter and grounded it, then stuck the red portion on the battery side of the fuse, getting a steady voltage there, on the other side, I get nothing. Would this indicate a bad fuse? My logic states that I should be getting voltage all along the line, but I could be wrong. Thanks in advance!

#1604957 07/07/06 12:14 AM
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To test a fuse you would "ohm it out", ala testing the resistance across the fuse itself. Should nil, none, 0, or at least CLOSE. if it is reading "XX MEGAohms", an infinity symbol (an 8 on its edge), or anything higher than about 2-3 ohms, then you have a bad mega fuse, which will cause:
ZERO charge to the battery
Constant charge indicator light on the dash

To also narrow down what it happening here, measure the DC voltage on the battery with the car running, across the terminals it SHOULD be 13.9ish-14.5-ish

Then shut the car off, turn on the headlights and leave them on for 60 seconds to remove the "surface charge" off the battery. Test across the terminals with the car off and you should have 12.0 volts or higher.

turn off you headlights and let us know what you found regarding the voltages and the resistance of that fuse.


'99 CSVT - Silver #222/276 In a constant state of blow-off euphoria.
Originally posted by Kremitthefrog:
I like to wear dresses and use binoculars to watch grandmas across the street.


#1604958 07/07/06 12:50 AM
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Your logic is correct.

Under no-current conditions, the voltage in all parts of the circuit should measure the same voltage potential.

Sounds like your megafuse is open.

Steve


98 Contour SE Sport 2.5 Duratec ATX The wifey's car 89 Taurus SHO - 246K miles 94 SHO ATX - 190K 1997 F-150 5.4L ATX - The Workhorse 150K. ANY THREAD WITH "OMG" or "WTF" ETC IN THE TITLE WILL BE IGNORED!
#1604959 07/07/06 01:39 AM
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Thanks for your support, oh by the way, the ford dealer here messed up. They told me over the phone they would cover my car under the wiring harness recall, I had it towed in this morning for the service and they refused to cover it in person . I made them pay for the tow in and out at least, in any case I'm happy to be making progress on this.

#1604960 07/07/06 02:16 AM
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One more quick question, can I buy the megafuse only at a ford dealer?

#1604961 07/07/06 01:09 PM
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Originally posted by Shtoms:
One more quick question, can I buy the megafuse only at a ford dealer?




Nope. It should be available at any decent autoparts store. Ask for a Littelfuse MEGAfuse 175 Amps. If the drone behind the counter gives you a blank look, you're at AutoZone.

Steve


98 Contour SE Sport 2.5 Duratec ATX The wifey's car 89 Taurus SHO - 246K miles 94 SHO ATX - 190K 1997 F-150 5.4L ATX - The Workhorse 150K. ANY THREAD WITH "OMG" or "WTF" ETC IN THE TITLE WILL BE IGNORED!
#1604962 07/07/06 03:13 PM
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Here is a good picture of a megafuse from Littlefuse

#1604963 07/07/06 09:48 PM
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OK then. A few burns and some good scrapes later I now have 12+ Volts all the way to the alternator post. The mega fuse fell apart in my hands when i took it out, it was corroded and shot, wouldn't hold a clean signal through it. I went to Ford too get my new one because Autozone couldnt understand what I wanted . Now, I am still not getting a charge. I used my multimeter to test every point on the line, 12 V at the alternator post when it's running. 12 V when its off. Correct me if I am wrong, I should see 14.5 on the alternator post when its running right?

The battery is an Interstate 60 month battery, that has been drained completely 4 times since January, 3 times in the past 2 weeks. The battery passed Sears die hard testing last week with flying colors.

Do you think it is a bad alternator? If so its going back to the shop for a warranty replacement.

#1604964 07/08/06 12:24 AM
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If you have 12V at the alternator itself while running, my first thought would be to make sure you have the alternator ground hooked up to the chassis, and the alternator.

Secondly, a faulty alternator.. yes.


'99 CSVT - Silver #222/276 In a constant state of blow-off euphoria.
Originally posted by Kremitthefrog:
I like to wear dresses and use binoculars to watch grandmas across the street.


#1604965 07/08/06 01:08 PM
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Quote:

Do you think it is a bad alternator? If so its going back to the shop for a warranty replacement.




Yes, it is bad.

Didn't I warn you about AutoZone?

Steve


98 Contour SE Sport 2.5 Duratec ATX The wifey's car 89 Taurus SHO - 246K miles 94 SHO ATX - 190K 1997 F-150 5.4L ATX - The Workhorse 150K. ANY THREAD WITH "OMG" or "WTF" ETC IN THE TITLE WILL BE IGNORED!
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