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Discussion Starter #1
My 07 Focus electrical systems ie the instrument panel, radio, interior lights, and turn signals will stop working every so often, has become way more frequent, the headlights will dim and brighten and the A/C will seem like its being changed from different blower strengths bu he A/C and lights seemed to be tied to acceleration and often stop when I brake. The only code that is popping up is a failing Mass Airflow Sensor and I was wondering if anyone else had this issue/s and if its a different fix then the MAFS.
 

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My 07 Focus electrical systems ie the instrument panel, radio, interior lights, and turn signals will stop working every so often, has become way more frequent, the headlights will dim and brighten and the A/C will seem like its being changed from different blower strengths bu he A/C and lights seemed to be tied to acceleration and often stop when I brake. The only code that is popping up is a failing Mass Airflow Sensor and I was wondering if anyone else had this issue/s and if its a different fix then the MAFS.
Alternator is failing. Good time to replace your battery cables as well.
 

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Discussion Starter #3 (Edited)
The alternator has been replaced along with the MAFS and the ignition switch. The only thing that's left is either a vacuum leak or a faulty oxygen sensor and I just tested for a vacuum leak and there didn't seem to be one.
 

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The alternator has been replaced along with the MAFS and the ignition switch. The only thing that's left is either a vacuum leak or a faulty oxygen sensor and I just tested for a vacuum leak and there didn't seem to be one.
Where did you get the alternator? Just because you replaced it does not mean it is not bad.
 

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A good alternator puts out 13.6 to 14.3. No more no less. A good battery will have 12.65 volts key off. Might I suggest you check before you dismiss the alternator? I went through 7 Autozone alternators in 2 years due to their rebuilder not replacing all of the diodes. They bench check fine cold but fail at operating temperature. One way to monitor what is happening is with a device like this. https://www.walmart.com/ip/Lighter-Temperature-Meter-Volt-Degrees-Cigarette-Amps-Over-Voltage-Charger-3-1A-Protection-Celsius-Adapter-4-in-1-USB-Blue-LED-Monitor-Car-Dual-Curre/982167805?wmlspartner=wlpa&selectedSellerId=503&adid=22222222228140411492&wl0=&wl1=g&wl2=m&wl3=250949359862&wl4=pla-417003487092&wl5=1026835&wl6=&wl7=&wl8=&wl9=pla&wl10=111840109&wl11=online&wl12=982167805&veh=sem&gclid=CjwKCAjw1_PqBRBIEiwA71rmtep0lBykMEAweTf8xxMit7qFUPLPgae4EmFPUq9Fz8_7FgxZ0sDlhRoCenoQAvD_BwE
 

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You could also have a bad cell in the battery. Have it load tested or swap it out for a known good battery.
 

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Discussion Starter #8
I had both my new and old alternator tested and both worked perfectly fine tested by both an independent mechanic and AutoZone and Advanced. Also I'm not 100% certain but I may have actually found the issue which is a missing Airflow Restriction Gauge/High-Performance Filter Minder/Airflow Filter Gauge.
 

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I had both my new and old alternator tested and both worked perfectly fine tested by both an independent mechanic and AutoZone and Advanced. Also I'm not 100% certain but I may have actually found the issue which is a missing Airflow Restriction Gauge/High-Performance Filter Minder/Airflow Filter Gauge.
That is a mechanical part and will not cause electrical issues but can cause the MAF code. You have 2 unrelated problems.. All 7 of my failed alternators checked good at Autozone.
 

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You need to monitor your voltage while you are driving so you can see what the voltage is while you are experiencing the problem.
 

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Additionally. Your car is 12 years old. Normal corrosion occurs at all ground connections. Remove the small ground wire that goes from the battery to the fender. Clean to bare metal on.the wire and the fender and reattach. There is another ground underneath the battery tray. It needs to be cleaned as well. Battery cables get old and cause issues.
 
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