New Jetta owner - I have questions

Hello

I'm new to the forums and a new Jetta owner also...i have a 1995 Jetta GL, 2.0 liter engine,automatic trans,122.000 miles on the clock......i got the car for $1500 which i thought was a decent price to pay for it beings gas is almost $4.00 a gallon where i live at...i have 2 questions for everyone here to try to answer for me

1 - the check engine light is on and a new O2 sensor was installed in it but still reads the code for the O2 sensor....is it possible it could be bad??

2 - the last owner cut the wiring harness to the fan motor and wired the fan direct so it would come on when u start the vehicle to keep the engine from overheating.....is there a relay that needs to be replaced so the fan motor comes on when its up to operating temp to not overheat and cool the vehicle down...i plan on reconnecting the harness back to original but need to know if i have to replace any relays to make the fan motor kick on as it did when before the wires were cut and spliced

thanks for any answers you can give to me for these questions...i'll have pics up soon of my car to show off..... Very Happy