I need a lot of help!

well, i don't think my v-tec has been working so a buddy of mine got his P28 ecu and hooked it up to see it would make a different... its reved a little higher but as soon as i turn the car on the check engine light came on and was on the whole time. and every time i stepped on the break the cruise control light came on....WHAT THE HELL IS GOING ON? then i put my P28 in the check engine light didn't come on at all or the cruise control...anybody have any ideas? should i just go to the junkyard and get a new wiring harness from a 92-95 Si hatchback/Ex coupe and a P28 ECU? i need some major help...anybody want to shot me some ideas