Oil Pressure Switch

[Forrest]

I mentioned this in another thread, but thought it was worth noting it in its own in case it helps anyone in the future.

The oil pressure circuit seems to be via a simple, normally-closed switch that earths the dash warning light via the block. It has a single electrical connector.

Its failure mode seems to be getting stuck open, thus causing the oil warning light not to illuminate when the ignition is turned to position 2. It was my bad luck that I only spotted this while working on the dash, thus wasting time. An easy test is removing the connector and shorting it to vehicle ground. The light will then come on and remain on with the ignition if the rest of the circuit is intact.

The actual switch/sensor seems to be common across a broad range of Volvo and Ford vehicles and hence is readily available. Volvo part number is 1347003 but I used Hella part number 6ZL 008 780-021.

The switch is located in the left hand side of the block just behind the water pump. Removing the turbo intake hose improves access. The outer “receptacle housing” part of the electrical connector will be fragile and is part number 1307035.

Replacement is fairly straightforward. You need a long 24mm socket to remove the old switch. I found mine was in quite tight and used a breaker bar from the front to get it started. Then it came out easily by hand. To complicate things slightly, the Hella replacement used a 22mm hex. The new one is best tightened from the turbo side using an extension and U-joint.

One of those jobs that is incredibly easy if you know what to look for and have the right tools; but then aren’t they all.