B2410 / B7510 Oil Pressure Switch Location

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B7510 & LA302 FEL & B2782 blower, B7510 & B2781 blower, B2410 & B2550 blower
May 25, 2016
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Ottawa, Ontario
Looking for some help from those who have "been there, done that" before me...

I'm troubleshooting a problem with the oil pressure switch on my B7510 (same systems apply to B2410). When I turn the key to the "on" position the battery lamp comes on but the oil pressure lamp does not. When I turn the key to the "glow" position the glow plug lamp comes on, but again, the oil pressure lamp does not illuminate.

I've pulled the instrument cluster, verified the oil pressure bulb is good (measured it and swapped it for the battery lamp). I've checked the circuit diagram and understand this is a simple circuit with the oil pressure switch being a "normally closed" switch providing a ground to one side of the lamp when oil pressure is absent. As oil pressure builds above 7psi the switch goes "open", removing the ground from one side of the lamp, thus killing current flow through the lamp. Simple Simon.

Now for the not-so-simple stuff. The Workshop Manual (Page 9-S22) shows a tiny illustration of the left side of the engine with ZERO detail as to the location of the oil pressure switch. I've gone hunting for that switch and can't seem to locate it. I must be blind. Or the loader frame is preventing me from getting my head in the right location to see the switch.

Anybody who knows where this oil pressure switch is located... I would sure appreciate if you could show me where it may be found in the engine. I suspect it's a simple matter of the switch being unserviceable or disconnected.

Thanks for your help!
 

D2Cat

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Look left side of block (while setting on seat, your left), below the head a few inches and towards the back of the block. It will, or should, have one single wire attached to it.
 

NoJacketRequired

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Equipment
B7510 & LA302 FEL & B2782 blower, B7510 & B2781 blower, B2410 & B2550 blower
May 25, 2016
432
68
28
Ottawa, Ontario
Look left side of block (while setting on seat, your left), below the head a few inches and towards the back of the block. It will, or should, have one single wire attached to it.
Thanks, D2... That's a hard spot to see with the loader frame attached so I bet that's why I missed it. I'm betting I've got a bad switch but if it's accessible it shouldn't be hard to change.
 

Russell King

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Try not to work under raised loader arms or the safety police may shoot you!


Al least block the rams with a piece of angle iron
 

NoJacketRequired

Active member

Equipment
B7510 & LA302 FEL & B2782 blower, B7510 & B2781 blower, B2410 & B2550 blower
May 25, 2016
432
68
28
Ottawa, Ontario
OK, thanks to D2Cat's helpful reply I have come to realize I'm a complete dope... The switch was right there in front of my eyes the whole time, very easy to find. OK, it wasn't as easy to find as I had thought, simply because the single wire spade-style connection had become disconnected, leaving me staring at the bare pressure switch rather than what I was looking for, a switch with a wire attached. DOH!

In the photo below you'll see the switch is located above and aft of the oil filter. Note the wire that's NOT attached to the switch. Its spade connector had flexed and opened up, thus it failed to grip the mating connector on the pressure switch. Some deft work with duckbill pliers adjusted the wire-side connector so that it now has some "stick-shun" on the switch-side connector.

Powered it up and we're good to go.

The second photo shows the default condition when the key is turned to the "run" position without the engine running - battery and oil pressure lamps are illuminated.
 

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