I had same prob with my 04 LJ, only worked on high. Ordered a Mopar blower motor resistor from amazon. Installed myself, took about 20 min total because of the tight space behind the glove box. It worked like new. There's a how to video on YouTube. Also, not sure if I had to, but I disconnected battery during installation as I always do when messing with the electrical components. Otherwise small possibility u could damage the new equipment, blow a fuse, or fry something else, which will then really confuse you and lead you to a whole lot of trouble shooting.