O2 Sensor?

[MT1083]

I pulled a P0135 code from my mustang. It is a "heater circuit malfunction (bank 2 sensor 1)". I can't seem to find a diagram anywhere, so can someone please tell me which side bank 1 / bank 2 is on. I also would like to know which sensor is sensor 1 / sensor 2.

 

[One Red Ride]

Bank 2

I can't seem to find a diagram anywhere, so can someone please tell me which side bank 1 / bank 2 is on.

Bank#1 is the side of the engine with CYL#1. Bank #2 is the opposite side.

Not positive about the sensor #, but it makes sense that the one closest to the engine would be #1 and the one post-cat would be #2. As long as your careful removing the old sensor, I'd replace the one closest to the engine and see if the MIL goes out. If so your good. If not, put the one you just took out (old one) in the post-cat location.