THIS is the reset switch for the 02 sensor.  their is a mechanicle swithc on a spring and it sets it off at a predetermined milage

Dan

"Fitz-Randolph, Douglas" <Doug@BEACONTEL.TV> wrote:

>Can anyone tell me what the function of this thing is? (Yes Malcolm, I
>already looked in the archives) It's a black box about 3" square that the
>speedometer cable passes through. A 5-wire connector is attached, 3 of 5
>contacts occupied. Located under the van just forward of the front, left
>wheel on a 2WD. Not all vans seem to have them. Just about all the
>Golf/Jettas I looked at at the junkyard on Saturday have them mounted under
>the hood up where the wipers are in front of the driver. On the Golf/Jetta,
>the wires from this thing pass through the firewall in the same bundle with
>the wires for the cruise control vacuum pump... but this "recorder" doesn't
>have anything to do with the cruise control system, does it?
>
>Thanks,
>Doug Fitz-Randolph
>Freeport, ME
>