2010 Mazda3 Lights Pulsating while stopped

[Kritterfur]

Greetings,

2010 Mazda 3 155k miles. Automatic Transmission with manual shifting option.

TCM was replaced 4 months ago by AAMCO. Recently while in gear and stopped by brakes, there seems to be a "Pulsation". The dash screen (displays time, temp and radio station), headlights and brake lights pulsate when stopped. The instrument panel illumination does not, nor the radio/AC illumination.

You can also slightly feel the pulsating through the brake pedal, but the RPM needle doesnt move at all.

Ive seen Service Bulletins online for 2012 and later for TCM/ECM reprogram. Not sure if its covered for a 2010 with a newer TCM??

 

[negusm]

That sounds like a weak alternator and battery to me. I can't see how a TCM will do that.

 

[Kritterfur]

That sounds like a weak alternator and battery to me. I can't see how a TCM will do that.

Thanks for the reply. I didn't mean to imply it was related to TCM, just offering recent history info

 

[JonhDe31]

Greetings,

2010 Mazda 3 155k miles. Automatic Transmission with manual shifting option.

TCM was replaced 4 months ago by AAMCO. Recently while in gear and stopped by brakes, there seems to be a "Pulsation". The dash screen (displays time, temp and radio station), headlights and brake lights pulsate when stopped. The instrument panel illumination does not, nor the radio/AC illumination.

You can also slightly feel the pulsating through the brake pedal, but the RPM needle doesnt move at all.

Ive seen Service Bulletins online for 2012 and later for TCM/ECM reprogram. Not sure if its covered for a 2010 with a newer TCM??

https://koko.bet/sports/

I’ve seen that before — usually it’s the alternator starting to weaken or a poor ground connection.
Check the battery terminals and grounds first, then test the alternator output at idle. If voltage drops below 13.5V, it’s probably time for a replacement or at least new brushes.