Help electrical issues 2011 CX-9

[Mazdawin]

Hello, trying to trouble shoot before I take my Mazda in on hopefully monday.

Yesterday my mazda had trouble reading the key (assumed the fob needed a new battery for locking and unlocking)

Yesterday evening i was driving when i felt like i was in a different gear so i pulled over and turned the car off (noticed check engine) then i could not turn the mazda back on.

40 minutes later the car could be turned on and i drove it a mile before the dashboard started to dim(time) windows could not be rolled up or down and the the unlock and lock was slow. The car then went off

After about an hour the mazda turned on again. I still waited. The check engine and battery light was on. By the time the tow truck came the car would not turn on.

The car does not register the keys (will unlock but not lock unless i do it manually). The car thinks the keys are inside. I can jump start the car and it will runs for a little bit.

Is this the alternator? Ignitor switch? Something completely electrical?

This is a 2011 Mazda CX-9.

 

[youri]

It sounds like the alternator. Basically, the alternator does not charge the battery so it dies while you are driving, but after being left alone for a long time the battery regains just enough charge to be driven a little bit. When you boost the car , you charge the battery a bit and it works for a little bit but runs out of juice fast and dies again.

 

[N7turbo]

It sounds like the alternator. Basically, the alternator does not charge the battery so it dies while you are driving, but after being left alone for a long time the battery regains just enough charge to be driven a little bit. When you boost the car , you charge the battery a bit and it works for a little bit but runs out of juice fast and dies again.

Yep, and this is easily tested at home. I use this:

INNOVA 3320 Auto-Ranging Digital... https://www.amazon.com/dp/ (commissions earned)

Set it to 12v and touch the probes to the battery terminals. With the car running, it should read ~14v. If it is much lower than that, the alternator isn't doing its job.