so my friends have put aftermarket stereos into many cars by now, and decided it would be a great idea to test the ground that we found... and doing so dimmed my interior lights and maybe something else vital. is there any way i can fix this or if you know what fuse to replace???? some help would make my day

 

How about a wire Color, or Year model. This is why the Newbie section is here, you would have been flamed badly in the main forum.

When posting a thread, make sure to include all the info to help the people that are trying to help you.

 

dont feel too bad. it happens look at the red parts
1988-91 Mazda RX-7 Stereo Wiring
Constant 12V+ Blue/Red
Switched 12V+ Blue/White
Ground n/a
Illumination Red/Black
Dimmer n/a
Antenna Left Rear
Front Speakers 4" Dash
Left Front (+) Blue
Left Front (-) Blue/White
Right Front (+) Blue/Red
Right Front (-) Blue/Yellow
Rear Speakers 6 1/2" Door
Left Rear (+) Blue/White
Left Rear (-) Blue/Green
Right Rear (+) Blue/Red
Right Rear (-) Blue/Green

 

Did they apply battery voltage to the ground for a continuity test? I recommend they get a multimeter with continuity function. Sorry to hear this.

 

i came acroos a few rx7 that cought fire to to the stock wiring some reson its fed up and burns the car down