Ceiling Fan light dim with fan switch
I have installed a new ibiza Hampton Bay ceiling fan. There was two cables from ceiling, black and white. And four from motor of the fan: green (ground) white (common), black (fan) and blue (light). I put together blue and black cables from motor fan with black ceiling cable, white to white, and discarded green (ungrounded installation, sorry). I installed the light fixture and then the double wall switch. In top is the fan control, with 3 speeds, and below is the light switch. But when a turn on fan in max speed, the lamp of the fan bright in high intensity. When a switch to low speed, the light decrease intensity, as the fan. What is wrong? please I need help!
NOTE: the light cables from switch wall are both black.