I am getting a high pitch sound coming from the glove box area, It comes and goes its definitely electrical. Stays on for 10-20 seconds goes away and comes back periodically. Any clues to what this could be? Thanks. Also SRS light is on and "airbag light indicates off. Dealer issue? Much appreciated.

The HVAC blower is in that area, perhaps the bearings are dry.

I've had the blower out of my 97 C280 , the description below might not be 100% but once you poke around there isn't anything difficult.

From under the dash, remove the "hush panel" , look up , there is a black cover held on with 2 white sliding clips, remove these clips and cover. Blower motor is screwed in from the bottom. Also. just to the left of the blower is the fresh air filter, probably a good time to change it anyway.

If you look up the instructions on how to change the fresh air filter, you will get to (I or near ) the blower motor.

Thank you. Will give that a look today. Much appreciated