Someone please help I've got a 2006 Mazda RX8 the key light won't come on it since I crossed the jumper cable wires then later replaced the battery I don't know if it's a relay all my fuses look good when I go to start the car the check engine light comes on it always has but I noticed now the key light will not come on At All when I try to crank the car. There's nothing but a click when I go to turn the key. Also the dome lights and the radio will not come on now. Any help would be greatly appreciated. also the light that says that a door is open or the security light all in itself will not come on at all when I open the door or turn the key now.

 

Check the fuses under the hood and in the door sills. Crossing wires is pretty bad, any number of things could have been damaged. The click you're hearing is the starter relay. Usually hearing a click and no start just means the battery is low -- which could be your case too, check it.

You needed a boost for a reason, and now if the new battery is low again, you may have a phatom current somewhere that runs down the battery while the car is off. One common thing is the trunk light stays on. If you open the passthrough the between the rear seats, you should be able to see if that's the case.

Otherwise, get a multimeter and read up how to hunt down phantom currents. It's not hard, just takes time.