I've never checked 02 sensor voltage wires with engine turned off, don't know if one of those circuits would show ground? The back wire on each 02 sensor should show ground, that is ground for the heater circuit. One of the wires for each sensor signal circuit, does show a ground symbol, I've never checked it the way your doing.
The autozone site has free wiring diagrams, you'll have to register your vehicle, it is free.
Also try www. Showmetheparts. Com/airtex/ when the site comes up, click on technical resources. It will ask for y--m--m just follow the links. It is mainly engine wiring and component locations. I don't know if I'm supposed to post links to other web-sites on this forum. This post may get erased. I have no connection to those sites.
Monday, August 3rd, 2009 AT 9:32 AM