Check engine light not working 1989 300e

[superxvillain]

so i bought this car not to long ago and i have been fixing things as they come. I am at the dashboard now with a broken odometer that i have fixed and a check engine light that has no response(turn the key to see all the lights on the dashboard and that one is off). I tried switching one of the lights but had no success. What else could it be? a fuse perhaps but i switched all the broken ones and put in new ones.
any thoughts?

Thanks~
Isaac