I have an '05 Mazda3s Hatchback and wanting to install a 4 channel amp. I can not seem to find a hole in the drivers side of the car or on the passenger side to pass a 4-gauge power wire threw. Is there a hole Im just not seeing or one I can use, instead of drilling a hole and using a grommet?

 

https://www.mazda3club.com/exterior-interior-audio-4/4gauge-power-wire-through-firewall-08-mazda-3-a-53225/ - shows you where there's a white plastic nockout behind the accelerator pedal. If you want to go through the drivers side, it works pretty well concidering the short distance from the battery to the hole.

If for some reason you want to go through the passenger side, just run wire through the same grommet as the wire harness that's behind the glove compartment. There shouldn't be an issue with magnetic fields if you run both power and ground all the way from the battery.

Good luck

 

Ok good, Ill look this up and see if I can figure this out later tonight. Thank you

 

If you check out the pics in my thread a few below yours there are good pics of power/ground cables ran through firewall on right side. I prefer to run them on the right myself. Also, I would run +/- both from amp to battery if it were me.

 

definitely run power & ground right to the battery (with fuse of course).
and for reference, its post #
https://www.mazda3club.com/showthrea...268#post414268 for the passenger side pics from KD053S. good job on the project & photo documentation of it.