Gauge Always Indicates High Pressure (Commercial & Motorhome)
- Disconnect wire at sending unit. Turn ignition on. Connect fused jumper wire from sending unit Tan wire to ground. If gauge indicates low pressure, replace oil pressure sending unit. If fuel gauge indicates high pressure, go to next step.
- Remove jumper wire. Backprobe instrument cluster with a fused jumper wire between terminal No. 21 (Tan wire) and ground. If oil pressure gauge moves toward zero, repair open circuit in Tan wire. If oil pressure gauge remains high, replace instrument cluster.