Where do I start with my oxygen sensor?

[WannaDriveFar]

Hey everybody,

So here's the story with my oxygen sensor so far:
- When I bought my van last Fall the OXS light on the dash never came on at start up but I didn't know any better.
- When I go to a shop in Boulder, CO I asked about a wire hanging under my van. turned out that was the wire for my oxygen sensor. The mechanic repaired it, the light came back on at startup and all was good.
- When I finally got my van home to Virginia I took it into the shop for a plethora of problems. Ended up needing a new engine. Screw the last guy who owned this van. Took 9 weeks to get repaired.
- A few days after I got it back, I realized that my OXS light wasn't coming on at start up again. I looked in the engine compartment and realized the red plug in the picture below was unplugged. I thought "Oh, they just forgot to plug it back in! Easy enough!"

Now that I've plugged it back in the OXS light still doesn't come on at startup. Where do I even begin to start troubleshooting this issue?

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1983 Vanagon GL Automatic

[vwjoel]

On all of the Vanagons that I have worked on the OXS light is controlled only by a counter that is connected to the speedometer cable. It has no connection to the engine or actual oxygen sensor. It comes on and stays on only after a set number of miles. The counter is located by the spare tire under the front of the van and can be reset. If the light does not come on at key on before the engine starts it could be a loose connection in the instrument panel or to the counter itself.
As far as your actual sensor goes make sure the connection is secure and be sure that the shielding within the green wire isn't torching the frame ground anywhere. Are you having any runnability issues or is it just the dash light you are concerned with?

[Steve M.]

As said that O2 light on the dash is just generated by and odometer counter only.
If you follow the speedo cable from the left front you will see it goes into a black box...probably a very dirty black box. Another cable comes out and goes up to the dash.
On that box is button to push in to reset the counter when the O2 light comes on. (It has to be pushed in a long way!)
That light does not mean you need to stop driving. It is just a service warning light.

Best if you put some electrical wire heat shrink over that cheap red plastic connector to keep it clean.
Put some "Dielectric Grease" on it first and then watch it squeeze out when you shrink the "heat sheink".
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