Diagnosis and Part Selection Advice:

How did you know this part needed replacement? Why did you choose a certain brand/part number?

1999 Dodge 3500, 5.9L 24valve Cummins, Oil Pressure Switch. Low pressure warning signal, and pressure ranging from 0 psi one second to 80 psi the next

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Part Comments

What came in the box? Were additional nuts, bolts, sealant, etc. needed for the repair?

I ordered and recieved an Airtex 1S6751 Pressure Switch in short order. Which was a perfect fit and fix for my problem.

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Repair / Installation tips:

You cannot reach the switch from below, engine mount and starter leaves a 2 in. space, and you can only see part of the wiring, which you must remove with one finger. You cannot see the switch from above, it is behind the fuel filter, above the rear corner of the ECM.

To reach the and remove the Pressure Switch is easier from above. First you need to loosen the two clamps holding the rubber tube from the intercooler to the intake plentum, rotate these clamps forward so the bolts and sharp edges on the back of the clamps won't cut your arm up. Reach in with your right arm, through this gap behind the hose, feel behind the fuel filter bottom and with your index finger find the wiring going to the switch and find the clamp holding on and lift clamp with your finger and slide the wiring off.

Now the fun starts. You will need a 1 1/4 deep-well socket, 6 in. extention, and a 1/2 drive ratchet (an air-ratchet won't work because of not enough room). put the combo together and slide it in socket first into the space behind air tube, work it around to get the socke on switch using finger tip feel, seat it on the switch. You will be using your right arm to do this. keep right hand on junction of extention and ratchet, carefully slide left arm between tube and injector pump and grasp end of ratchet handle end, apply pressure to break the switch loose, you can now remove the switch your fingers. Leave your tools in in the area. Reverse process to replace with new switch, using finger itp to find hold in block. Replach switch, tighten and replace wiring, Reverse process to put clamps back and finish.