I have a problem I hope you can help me with, when I went to put a new transmission control module in my 07 Mazda 3i, the
transmission control module was not under the battery like it is
supposed to be. Can one of you tell me where it might be?

The 2007 Mazda 3i does not have a separate TCM module -- it is integrated into the engine computer.

 

On the 2007 Mazda 3i, the Transmission Control Module (TCM) is usually located under the airbox, near the driver’s side fender, rather than directly under the battery. Try removing the intake tubing and airbox to check. If it’s not there, follow the transmission wiring harness—it should lead you to it. Let us know what you find

 

The 2007 2.0L 3i does not have a discrete transmission control module. The 2.3L S does have a discrete transmission control module.