The lower RPM switch is located on the driver’s side of the engine, between the pushrod tubes for cylinders 3 and 4. To access this one, you will need to remove the engine tin, which means a couple of exhaust nuts as well. Which means you’ll probably strip at least one of them, so proceed carefully. The sender should be 0.3 bar/4.4 psi, and is light brown in color. If the incorrect sender (a higher pressure unit) is fitted to the engine, it will give a false warning when pressure drops below its allowed range. Note that the sender will state a range of pressures, not an exact pressure. The range should include the numbers stated above.
The higher RPM switch is located near the crankshaft pulley. This one is a little trickier to get to, but if you remove a couple of belts, and push the exhaust shield out of the way, you should be able to get a socket on it. It helps to use a reducer on your ratchet to make a 1″ extension. This sender should be 0.9 bar/13.1 psi, and grey in color. On my most recent vanagon, I had a Canadian VW factory rebuilt engine, and this sender was the blue one, rated for roughly double the pressure of the grey one. No wonder I was getting a light and buzzer!!
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