Alternator

MICHAELDEAN

MEMBER
2007 FORD ESCAPE
3.0L
V6
AWD
AUTOMATIC
136,000 MILES

I got a good alternator off a 2005 and it bolted up and the hook up was the same I started it up and took it a ride the battery light came on and went back off. So I took a ride and the light stayed off for about half house then came back on and went back off then came on again and drained my battery. I tested it it said I had a good battery but alternator said it was not charging what could it be?

Thursday, April 27th, 2017 AT 3:35 AM

2 Replies

HMAC300

MECHANIC
48,601 POSTS

Check all fuses and fusible links in picture, if all are good then have a mechanic scan for codes for a possible can/bus problem. Also, have belt checked and tension-er as recommended replacement for both is 60,000 miles you need a gauge to check it.

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Thursday, April 27th, 2017 AT 6:00 AM

STEVE W.

MECHANIC
14,215 POSTS

On Ford trucks the alternator itself is self contained BUT the PCM actually controls the internal regulator. It turns it on/off as needed to charge the battery. The first thing I would do is check every connection, a loose wire or even a corroded pin can be enough to stop the system from operating properly. If it discharged the battery I would suspect the replacement unit has a bad diode in it. Easy test. Disconnect the battery cable from the back of the alternator, with the key off and everything shut off, connect a test light in between the cable and terminal. If the light comes on, you have a problem as current is flowing in a system that should be off.

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Thursday, April 27th, 2017 AT 11:12 PM