1992 S500 with 119 engine
Engine idle rough. Hook up hand held meter got code saying
1. O2S 1 signal, shorted or open circuit
2. Starter Lock-out and reversing lamp SW S16/3 fault
3. Low volts, voltage supply circuit 15R.

I am ordering the oxygen sensor AND starter lock-out and reversing lamp switch S16/3.

Is there anything to look out for while changing these parts, apart from take the negative off from the Battery?
Thanks everyone.