mtm

Daughter's car. She says that the speedometer quick working one evening. Next day the car quit, the battery was drained. Thought it was the alternator since battery volts didn't increase when vehicle was started, dropped from 12.7 volts to 12.3 volts. Changed alternator but same results. Can start car and remove ground from battery and car quits. I have checked various things, fuses and wires to alternator from battery. I have replaced the battery and alternator with no luck. Not sure if the speedometer not working has anything to do with battery being drained????? Have also changed the speed sensor in attempt to fix speedometer but no luck. Any ideas??????

Bert

Check the voltage at the big plug on the alternator. It should show battery voltage. If not, there's a problem between it and the starter connection. Repair that and see what happens with the speedometer.

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Bert

mtm

I checked the voltage at the alternator where the cable from the battery bolts to it. It was the same voltage as the battery. Is that what you are calling the big plug?? Or is it the snap on plug on the alternator?? Not sure. Could the speedometer problem be related to the battery drain problem??

Bert

The wire you checked is the one I was referring to. When the engine is running, do both places record about the same voltage when it's running? It should be around 14 volts when the battery is fully charged. With the key on, there should be power at the green/black wire and on the red wire if it's a late production or Duratec

I don't see how the speedo has any connection unless there's a problem in the instrument cluster itself. I doubt it though. Get the charging system going first.

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Bert

mtm

I had 12.6 volts @ both battery and alternator with key off. With key on 12.45 @ both and with running 12.3 @ both. Did notice that none of dash instruments are working. This is probably cause of battery drain?? Any ideas??

Bert

Sounds like you did all I can think of without testing it myself. Did the place check your old alternator to see if it was bad?

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Bert

mtm

Yes, they checked it and said it looked OK. I read sometimes test may not be accurate. I bought new one to try but got the same results.

Bert

What's the production date on the car and is it the duratek?

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Bert

mtm

Manufacture date is 02/99.

No it is not a duratec, 2.0 liter 4 cyl.

Where do the 2 wires on the snap plug on the alternator go ?? Looks like one goes to the starter?? Could this be my problem if either wire is bad??

Can you check voltage of alternator by removing wiring from battery and running engine(after it is started)??

Bert

Here's the main part of the diagram. Yours would be the early production.

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Bert