UB oil pressure switch

molinegb · Jun 29, 2014

Doing wiring on UB Special diesel. Wire disconnected to one side of oil pressure switch.Where does it connect to? It has a large eyelet. Oher side connects to hourmeter.

Jim Haugen · Jun 29, 2014

It sounds like it needs to pick up a positive voltage. The oil pressure switch is a NO (Normally Open) switch. When the engine is running, oil pressure completes the circuit to the hourmeter.

Seems like there ought to be a fuse in there somewhere.

molinegb · Jul 1, 2014

Supply comes from ammeter. According to hourmeter large eylet is connected to ground somewhere.

Jim Haugen · Jul 2, 2014

If the B+ is from the ammeter, then it needs a ground after the oil pressure switch so that the hourmeter will run only if there is oil pressure present.

molinegb · Jul 2, 2014

Being an electronics tech by trade I know how the switch works.
Apparently the hour meter and the diesel starting aid were options. Most oil pressure switches were mounted and teed into oil pressure line where oil line comes out of crankcase. Being dealer installed options my dealer decided to tee into line at oil pressure gauge in dash. The large eylet probably was mounted to 3/8 bolt on crankcase.

UB oil pressure switch

molinegb

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Jim Haugen

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molinegb

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Jim Haugen

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molinegb

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