Fuel Gauge Wiring Issue with Ron Francis Wiring Harness

[Boula]

I was having issues on my MK4 build with getting the fuel gauge to get any reading at all through the Ron Francis (RF) wiring harness. The gauge would flicker when turning onto accessory or start mode so it was getting power, but I couldn't get any reading on the gauge from the fuel level sensor. I tested the sensor and it was sending a signal. I tried the extra, independent fuel level wiring that came with the gauges and the gauge worked fine. After nearly giving up and running the independent wiring, I realized that the harness wiring and fuel gauge wiring connector didn't match. The connector uses a 3-wire connector, but the wiring is only 2 wire. The gauge side of the connector is pinned on the 1 and 3 wire and the harness wire is pinned on the 1 and 2 wire. I switched the 2 and 3 pins and it works great.

Maybe others have had similar issues, but I didn't see any posts in my research, so I'm sharing this in case anyone else runs into the same issue.

[phileas_fogg]

Unfortunately pin mistakes happen. Kudos to you for finding yours!

On the dozen or so cars I've seen one personally, I've found one; the offending connector provided power to the coil, resulting in a delayed first start. As a best practice, I recommend checking each and every connection for the harness - regardless of harness manufacturer.


John

[JohnK]

Agreed - pin mistakes do happen from time to time. Nice catch finding yours without going crazy. I found one mis-pinned connector and one damaged pin in my harness. The damaged pin was obvious, as the two connector halves wouldn't plug into each other. The mis-pinned connector was just a lucky catch as it was one of the smaller connectors and it was somewhat obvious that the wire was in different places in the two halves. These sorts of issues can be a real PITA to troubleshoot sometimes.