My rearview mirror on my 99 Escalade quit auto dimming. Turn the mirror on and the temp shows but the power light never comes on. If I press the little switch on the bottom of the left side the power light comes on for a second then fades out. if I hold the little button in the ligh comes on until I release the button. I replaced the mirror but the problem is still there.
P.S. the temp and compass both work OK.
Any ideas or help?

Thanks