Alternator voltage

Tiny
RANDALL729
  • MEMBER
  • 1994 LINCOLN TOWN CAR
  • 4.6L
  • V8
  • 2WD
  • AUTOMATIC
  • 142,000 MILES
The battery isn't getting charged when the car is running. The multi-meter reads 0.0 volts at the alternator positive stud with car shut off. With car running the reading is 4.7 to 6.0 volts. I had checked the alternator a few weeks ago and was getting 14.5 volts output. I am not understanding why this is? There is a 10 amp fuse for the alternator and is not blown. Any help would be appreciated. Thank you. Randall
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Tuesday, August 6th, 2019 AT 3:47 PM

3 Replies

Tiny
ASEMASTER6371
  • EXPERT
Good evening,

That wire comes directly from the battery. Check the cable back to the positive side of the battery for any damage.

There is a fusible link that is in line for protection at the under hood fuse block. Check that and see if it is broken.

If it is, replace the link and the alternator as that is the reason the link failed.

Roy
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Tuesday, August 6th, 2019 AT 4:31 PM
Tiny
RANDALL729
  • MEMBER
Thank you for the wiring diagram. Was helpful. Update of problem. The inline fusible link was okay. I cleaned up all the wiring connections. The multi-meter readings are alternator stud 11.78 volts, battery positive 11.78 volts, under-hood fuse block stud 11.78 volts. I had the car running and air conditioner on while using the multi-meter. The volts seem low. Shouldn't the alternator be putting out 14.5 volts to the battery? It is a 130 amp alternator and was new just recently.
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Wednesday, August 7th, 2019 AT 1:20 PM
Tiny
ASEMASTER6371
  • EXPERT
The alternator needs at least 12.2 volts to work. Charge your battery to 12 6 volts.

Roy
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Wednesday, August 7th, 2019 AT 1:54 PM

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