There is a pair of connectors in the cockpit that carry the wire coming from SBF-5 to the main fuse box to fuse #13, as well as to the ECM, OBD connector, fuel pump relay, and main relay. The connectors are identified as F44 and B61, rectangular 8-pin connectors up below the dash on the driver’s side.
In addition to the connection from SBF-5, the other seven wires in the connector are for the headlights (3), power seats/windows, main supply to the ignition switch, power to the ignition relay, and a ground wire. If the headlights and power seats and windows do not work, the connectors may not be attached. (Note, the seats and windows etc don’t use SBF-5, so this is just to test if the connectors may have come loose.)
There should be continuity (zero or near zero Ohms) between the underside of the SBF-5 and fuse #13 in the cab fuse panel. Disconnect the battery and remove the SBF-5. Check for continuity between the two SBF-5 contacts on the fuse box itself and the positive battery cable. One of the two contacts should have zero Ohms in the cable. The other SBF-5 pin in the fuse box should be the one that goes to the cab and fuse #13. Check for continuity between that SBF-5 pin and fuse #13. If there is no continuity, then there may be a break in the wire.
The wire harness between the main fuse box and the interior of the car runs from the bottom of the fuse box, through an opening in the left fender inner panel, and then runs to the rear inside the fender (above the wheel well liner ) until it enters the cab through a jacket near the A-pillar. There have been instances where the harness has been worn or cut along that length, sometimes due to a left front fender crash that damaged the harness, but was not noticed when the fender was repaired. . There is also an area closer to the A-pillar where there is no wrap around the wires so the individual wires are more exposed.
In this harness diagram, F37 is a connector under the main fuse box that has the SBF-5 wire coming from SBF-5 and going to F44 in the cab. The red highlight identifies the harness between the main fuse box and F44 in the cockpit.
See attachment 547269
