Ford 3600 air filter restriction switch plumbing

[gwbeyer]

My Ford 3600 diesel is missing the air filter restriction switch. I see the nipple on the air tube that it screws onto, and the wiring is there, but where do I route the other threaded end of the switch? I haven't found any photos online showing this.

Gary

 

[Destroked 450]

The switch screws onto the air pipe nipple and the wires connect to the switch

 

[a49deere]

IIRC, the threaded end that doesn't thread into air intake is made so that the wire connector just pushes over the threads!

 

[gwbeyer]

This is the switch that New Holland sells as a replacement. I haven't purchased one yet, but it appears one screws the plastic base onto the air pipe nipple. The wires obviously go to the spade lugs. I'm asking where the threaded metal end goes.

 

[Jim.ME]

This is the switch that New Holland sells as a replacement. I haven't purchased one yet, but it appears one screws the plastic base onto the air pipe nipple. The wires obviously go to the spade lugs. I'm asking where the threaded metal end goes.

Metal end goes into the air pipe nipple. The plastic end would be open or just have a dust cover/vent made into it, no threads.

 

[Sean in PA]

Jim is correct. The threaded metal end screws into the nipple. The plastic open end should just stick out. There is a diaphragm inside that resists getting sucked in by the vacuum on the threaded metal end until the suction gets above a certain point, which is when the air filter is too clogged and needs to be replaced. When the diaphragm finally moves from the suction, it actuates the electrical switch inside that closes the circuit for the warning light on the dash.

 

[gwbeyer]

Well, that all seems logical, but the nipple on my air pipe is a male thread also. If I am to attach male to male, I'll need an adapter. It didn't seem likely to me that NH would sell it as a replacement if that was the case. I suspect they are just using a generic part and selling it for a premium price...

 

[Jim.ME]

Well, that all seems logical, but the nipple on my air pipe is a male thread also. If I am to attach male to male, I'll need an adapter. It didn't seem likely to me that NH would sell it as a replacement if that was the case. I suspect they are just using a generic part and selling it for a premium price...

It is not uncommon for those to use a coupling to screw into. If you did not remove the old switch, it is entirely possible the 1/8 NPT coupling was removed with the old switch. It all depends if the air tube had a male or female tap for the switch. And adding a coupling is easier and less expensive than a special switch (JMHO). The parts book shows a 352474S coupling between the air tube and switch for some of the 3600s.

 

[gwbeyer]

Great answers Jim and Sean. Thank you!

 

[Jim.ME]

Great answers Jim and Sean. Thank you!

Just go to a parts store or hardware store and get a 1/8"NPT coupling, brass, steel, or malleable, plain or galvanized, any one of them will work if you don't have one around.