I hope that I am not the downer in this thread. I have the same issue on my 99 Trep. I replaced the resistor with a new one. It work great for a day and then went back to only working on high. So then I practice the definition of insanity and did the same thing expecting a different result. I put another one and well,,,,,, the definition held in that it also lasted only about a day. Something is causing the diode in the assembly to go out. I have not had time to trouble shoot any further. Hope you do not have this issue.