Help! Losing power from somewhere!

[Trason620]

I recently purchased a 2013 Ford Fiesta SE with 75,000 miles. The air initially worked fine. After driving it for 9 days I lost AC and was told the AC compressor clutch, bearing, hub and bearing was likely bad. I bought a kit and replaced it and during replacement realized the AC compressor itself was bad so my friend left the coil off and the AC compressor disconnected. He assured me this would not affect anything other than not having AC. The next day my check engine light again came on and I lost all power and it died. He told me my alternator was likely bad from that AC compressor being bad so long, so I bought a $240 alternator and replaced it. It’s still not charging the battery, though. The voltage is staying around 12V and drops to around 11.2-11.6 when anything is turned on in the car. We’ve checked every connection including the alternator, cleaned and even grinded connections, checked every fuse checked the harnesses, and I’m at a complete loss. The battery is testing good and I’ve tried an older replacement battery that he had laying around that had a full charge and it didn’t help, either. I’m a single mother and I don’t know what to think about this situation but it’s important I figure it out. Thank you I’m advance to anyone who can help.

 

[scotman]

You need to connect a generic OBD scan tool to the OBD port under the bottom edge of the instrument panel. When you got the check engine light it stored a malfunction code in the processor. That’s where your work should start at.

 

[Handy Andy]

When you get some time, did you check the red cover terminal block on the Battery?

The alternator and Starter run to it thru a large RED cable. The problem may lie in the Starter to Alternator cable jumper that connects the Alternator output cable to the SOLENOID side of the starter.

IF the system is not boosting up the voltage, the cable may need service. Your Fiesta should not need to have any "ALTERNATOR reset" done. In USA models - they drop in and if the connectors are not checked for "old-connector" memory - the new alternator has the same connector style, but those terminals might need to re-checked and even burnished and re-bent to make good contact to the plug side on the alternator itself.

Old - connector refers to the previous connections on the terminals may not exactly fit and perform like OEM due to the minor changes in old connector seating to the new connector fitment. Does not make the best contacts if not retensioned re-fitted to what the old terminals had in gap, spacing and tension to make that connection. (Squeeze the terminal closed a little bit to reapply that tension onto the lugs of the alternator - if carefully done - else - replace it with a new pigtail)