Annoying sound from inside my cab
 

I just bought a '98 blazer about a week ago. I love it and have already turned a few wrenches working on her but I have this weird noise that I cannot figure out. It sounds like a loud squeaking or blaring noise sometimes when I start her up sometimes it lasts almost a min sometimes just a few seconds and it doesn't happen all of the time. It doesn't sound like a programmed error or warning type of noise although it may be. my father-in-law (who has worked in GM parts for over 30 years) says he thinks it is something in the air system (heating a/c). the only thing I know for sure is it is not coming from the engine and i am pretty sure it is coming from the dash area. Any help or insight would be greatly appreciated.

I'm sorry, I read the title of your post and thought it had something to do with my wife riding in the passenger seat.

Actually I had a similar noise. Traced it to the old air bag. Nothing I could do.

I thought the same LOL
BUT I tried to resist

Try to record the noise for us
Try flipping of the the heater blower when it happens to see if the noise changes
I have heard blower motors make some odd sounds

X2 on the blower motor.

X3 blower motor

Thanks for the help guys it doesn't happen very frequently so it's hard to record it but if I am able to record it than I will post it. I am pretty comfortable working on my engine and trans ect. but tearing into my dash makes me nervous. If it is the blower motor, how difficult is that to replace.

Blower motor isn't bad at all. Remove the PCM/VCM & coolant reservoir. There are marks on the evaporator housing that show where to cut it, (with a utility knife) so you can get to the motor. 45 minute job.

So i have tried messing with the air controls evrytime the "wife" noise comes back and it doesn't seem to have any effect. The airbag light on my dash comes on and off periodically so i am leaning toward that being the source. Thanks for the insight.