w124 300e blower fan works sometimes

[whair]

I have a 1991 300e. after my last service, my fan only works sometimes.

Sometimes it'll work right when i start the car, sometimes randomly starts after 15 min of driving.

sometimes it doens't work at all during a given day.

All fuses are fine, including the blower fuse

Some of the things i noticed is:

when the fan doesn't work, the control buttons like fan speed and blow options don't light up. Also the circulate fan red led doesn't turn on when i hit the switch.

My mechanic thinks it's the blower regulator. but how could it all of a sudden starting having this problem after last service. Makes me think something was messed up on the last service or something.

Let me know if you guys have any ideas. thanks