How do I reset it?

When I check the engine codes I get the following:

E49

then

E52

then

.E.E

then

E49

then

.7.0

Also my side light won't run...I have checked all the fuses and changed all the bulbs

Also my side light won't run...I have checked all the fuses and changed all the bulbs

Drezee, what year is your car? Myself and another forum member both have 90 Devilles and we BOTH have this same code. My car gives out the EXACT same sequence as your does. Maybe we can help each other fix it. As far as getting rid of the check engine light, I think there is a way to clear the codes and shut the light off. Anyone care to shed some light on this?

Read the other user's thread. It also has a link to my thread. E49 is addressed in the linked thread and E52 just means the codes have previously been cleared.
http://www.cadillacforums.com/forums/showthread.php?threadid=2597

E49 is an AIR system fault which is the air injection system (air pump). And the E52 is from the ECM fuse and/or the battery being disconnected or going dead, NOT from simply clearing the codes.

I had to replace my Blower control Module, but in the process I knocked off a small tube right behind the intake and right infront of the BCM. Once I reattached it, the light went off the next day. Hasn't been back on since...
but a funny thing started happening. All of my electrinics just all of a sudden reset while I am driving once a day after about 5 minutes of driving. It only happens once. My speedometer goes to max and my airbag light comes on. Doesn't really effect anything, but it is just weird. Hope this helps...

I have a 1990 Sedan Deville Classic with 190K