Here is the problem:

Rear pass side signal bulb blew out. Replaced. Altenator died. Replaced and charged battery. One week goes by and turnsignal builb stops working but is not blown, and the headlights start flickering and barely emmit light. They pulse once per second. They also make a sizzling sound.

I need some advise on where to start.??? Also got a code 13 for 02 sensor.

 

I'd start by running a secondary ground from the headlamp harness to the battery's - to see if that fixes the lighting problem. Hopefully, the O2 sensor problem is something else or that's going to not be fun to track down (unless it's just a bad sensor, of course).