Alright I want to try and swap my broken ecu/voltage regulator for a buddies real quick just to see if thats whats wrong with my jeep. I have a 97 tj 4cyl and he has a 4.0l sport 97 tj. The Ecu's are connected the same and look identical. Can I put it in my jeep to see if thats the problem without ruining his component or will it ruin the computer by putting it in a dif jeep. Dealerships dont seem to care or give a rats butt about people that didnt buy jeeps from them or they dont have 97 tj parts (is what they told me.) The part is not expensive about 250$ but I am worried thats not the problem and if that part touches my jeep I can not take it back (dont know how they know but whatever.) However I am sure that replacing the ecu will give me about a 90% chance that my tj will run again. I have replaced the battery, alt, cables and the jeep runs fine (and starts fine), but the battery will not hold a charge. So sorry for long intro but main question is can I put his computer in my jeep and start it to see if thats the problem or will it short circuit? Thank you!