When i married my husband he owned a mazda mx6 with a bad tranny. He had bought it from a local dealership and was in love with the car. When we found out how much it would cost too fix, (almost 2000), we decided to see about buying another one. Instead we bought a 626, of the same year. (89) The cars look identical inside and under the hood. So we figured we would use the mx6 for parts. The problem we are having though is the past owner of the 626 pulled his stereo and hotwired the car, screwing the wiring. We got it fixed or so we thought. Any time the key is in the ignition it makes a loud buzzing noise. Nothing you do will turn it off or make it stop and it is terribly annoying. Anyone know what this is or how to fix it? ALso does anyone know if we will have any problems switching out parts? We were flirting with the idea of switching out engines.

Depends on the engines. There's a lot of work involved with switching a 2.2 non-turbo to the 2.2 turbo and vice versa. Also you didn't say if the trannys are standard or auto. If you are going with an auto, you might run into grief later again and have the same 2-grand repair bill.

I have looked for parts for my 88 626 and found the mx-6 is a different beast in many ways. Eg. rear bumper cover looks identical yet the mounting points and the size are slightly different. Climate controls, different on an mx-6. Have a good look at the two cars before you get bogged down in a switchover. I know for sure they are the same platform with the same basic 2.2 motor and tranny.

Don't know about the buzzing noise but it's pretty easy to take the steering column covers off and have a look. Four or five screws on the bottom plastic cover and you can basically see the entire key/ignition wiring harness.