its actually a tough connection. even if you don't have wire issues like you did, its a high current joint that's subject to regular vibration, rather large hea

its actually a tough connection. even if you don't have wire issues like you did, its a high current joint that's subject to regular vibration, rather large heat swings, condensation and high humidity, etc. and they usually put it in this little box thats hard to get to and easy to subject to damage when installing or pulling the unit out for troubleshooting.