Just descreened MAF on a 99 silverado and finished installing sensor.But forgot to hook it up,went for a drive and ses light went on.I pulled fuses ECM 1 and ECM B to reset light and it worked.I have to go and get inspected and I was wondering if pulling the fuses resets the light or does it clear the code.I don't want to fail (it costs $48)because I have a stored code.

 

You can have up to two codes so you should be fine!

 

pulling the fuses to PCM would case ALL I/m 240 smog tests to revert back to a non complete state and have to go through the self tests until they are completed again.
Depending on how you drive and the amount of valid drive cycles would then depend on how many are completed so if you have do scanner to look at I/M 240 tests wait a few days before doing any smog test.
If the stored code is smog related and present it could cause you to fail smog depending on what the code is for it maybe pointing to a function like a 02 that is also causing other functions to fail the IM tests.