The rear O2 sensor heater is done in my mother in law's car. It's a base model 1996 Volvo 850 with manual trans. I've done this before on other cars and know it's best to go for the oe style connector. Online research shows a denso and bosch sensor. I've also noticed there are 2 options with different length wires. My question is when did Volvo switch to a longer wire connector? Reading has shown they did this to protect the connector from contamination. This isn't my car and I'd really only like to go under there once to do the job and not another time to measure the wire. Maybe I can tell from up top under the hood?

 

If you want to do it once, get the longer wire to be safe and go OEM.

 

Well there should be the sensor with the short wire and the pigtail to go in the middle. The pigtail is what catches the contamination.

 

That is the OEM part number listed on this page.
http://www.fcpgroton.com/product-exe...ategory_id/169
I know if you buy it from the Dealer the pigtail comes with it. I am not sure if it does through that site.