My new JL Sahara has blind spot and cross traffic sonar with LED lights. I recently purchased a Roadmaster wiring harness for flat towing from Etrailer and took it to my local 4 wheel drive shop. They installed it. Now, my blind spot/cross traffic sonar indicators aren't working. I took it to the local dealer and they won't touch it because they say I modified the wiring harness. Any ideas about what's gone wrong?