I have been getting the check engine light indicating a bad O2 sensor heater. I ordered a generic one that has no plug as it was about half price for a Borg Warner. Yea I know but after all it is an old car. Anyways their direction sheet is a hodge podge mess and makes figuring out what is what pretty iffy and it's no surprise their puzzle match up doesn't include wires the same colors as mine. So does anyone know which wire does what on the 4 wire O2 leads? The wires are WHITE GREY BLACK BLACK. Also , does it matter if the blacks get reversed???? I can't imagine it would or they would be different but ya never know. Thanks.