[brucepick]

Has anyone had trouble with their SG losing it's OBDII Mode setting or losing it's accumulated data? That's what mine was doing. Since about last November or so. It's been a long time.

The SG people replaced the board twice and also provided a second connecting cable. After the 2nd board replacement gave no improvement I decided it mustbe due to something going on with the car, not the Scangauge.

I think I finally resolved it by isolating two power hungry circuits from the power bus that provides 12V to the OBDII port. The horn and headlights now get power separately from the battery and not via the maze of 18-22 ga. wires in the oem harness.

I installed a very heavy (8-10 ga.) tap off the battery to a new junction box that feeds power to three relays, each via a separate fuse. All the other added wiring is minimum 14 ga., some are heavier. One relay powers the horn, the other two power the high and low beams respectively. Each relay is triggered by the wire that formerly ran the horn or headlight. In the case of the headlight relays, they're run off the passenger side headlight socket. All relays I installed are fitted with diodes across the relay coil terminals, intended to eliminate the strong back EMF that can occur when the coil's field collapses after power is cut. (google it or ask me if you need details on that last bit)

Today after completing the last of the headlight relay installation I made extensive use of the horn and both high and low beams and flash function. The ScanGauge didn't fail even once. My commute is 50 miles each way. Since it was rainy I also was running the wipers and intermittently the a/c compressor and blower fan so I think I taxed the system pretty well.

Anyone else have problems with a ScanGauge failing mysteriously?