Amidst my failures today i did happen to install my cdl switch and do the pin7 mod, yet this was amidst my failures. after installing the cdl switch the indicator ligths would not light up and cdl would not lock, i checked the switch again and again and seemed to be connected fine so i checked to see if it would lock when placing the trans in low (prior to doing the pin7 mod) and no such luck. after seeing this i proceeded to complete the pin7 mod and was successful as the cdl still does not engage in low . are there any common reasons for the cdl not to engage.