Oil pressure sending unit - general wiring

[Wolvesboy]

My oil pressure reading is static - either at 30 or 55/60 and never moves apart from on/off.

Oil level is good and never moves.

I changed the Oil Pressure switch with no change.

Looked over the OP sender unit and even though it has 2 "connectors" there is only one wire going to it (no other wire dangling anywhere). My OP switch is the exact opposite with one "connector" and 2 wires going to it!

Is this correct?

I can offer a photo if necessary.

[scottliv]

Yes it is correct there should be only 1 wire as the return is via the earth path of the engine block. Try taking the cable off the sender and touching it to the engine casing to ensure you get smooth full scale deflection on the gauge.

[Classic Chim]

Then try grounding out your sender by adding another wire from sender to chassis.

[bobfather]

Wolvesboy said:

I changed the Oil Pressure switch with no change.

I assume you mean oil pressure sender, the oil pressure switch is an entirely separate device that operates the low oil pressure warning lamp on the speedo gauge

[Steve_D]

There are two versions of 2 terminal senders.

One uses the body as the ground then one terminal is the pressure sender for the gauge with the other terminal being a switch for an oil pressure light.

The other version is just a sender for a gauge but grounds via the second terminal rather than through the body.

Steve

[Wolvesboy]

Thanks for the quick replies fellas.

It does not seem right that the OPswitch has 2 wires into it - cannot be message and earth as both into the same connector. Message to warning light plus?? I am sure my Cerb 4.5 only had one wire in and earthed through the body.