I dont know when l can find a switch button of revers ligth on my cherv optra 2007

Sounds like the window motor is out. Behind the door panel of affected door

The HOLD button is for the transmission stop changing gears. It is mainly used for lower gears going or down up large hills. Its best to leave off.

either ur crank sensor is faulty or hold switch on shifter console.

l,do not know much about that l advise you contact a qualify service personal

flashing is a severe condition, most cases it is from random multiple misfires, i would get it checked soon.

Rear defrost/defog is electric.Rigger says check the fuses and put the proper amp fuse in.Check owners manual for fusebox position forr rear defog.

bad brake light switch

could be your reverse light switch on the transmission has gone bad

As far as your back up lights....check the neutral safety switch. This was a BIG problem on the 98-99 Cadillacs.

On the heated seats....you'll have to check for voltage at the harness where it connects to the seat(s) if you can do this.