About a week ago my keyfob did not work. Replaced batteries, keyfob, and it still did not work. All my fuses were good but I moved a couple around and the keyfob worked again but both front windows and side mirrors were not working.

Then I did a complete system reset, disconnected the battery, and everything started working again. This worked for about 2 days and this morning the drivers window and side mirror and not working but everything else is. Sound like some kind of software bug or issue....any ideas?

Thanks

Most everything on these cars ( 98 and up ) goes through CAN bus. Water or a failure in one of the modules can cause all sorts of issues. ( my C280 is a 97 so I can't offer any specifics )

The key fob will start the car even if the battery is missing, the bat is just there for remote locking / unlocking.

Also, if the cars cranking battery is failing, it can scramble the fob. If cranking voltage drops too low, the challenge / response activity with the key does not complete leaving things in a limbo. The key must be replaced and if too many keys are issued, the EIS ( Electronic Ignition Switch , the place that you insert and turn the fob ) replaced unless you get a hold of a china e bay programmer.

I have had cranking batteries that would crank forever but drooped too far under a load. Rather than a 12 V battery they were a 10 due to a shorted cell.