M939 low air switch.

[Floridianson]

I just went to the truck parts shop and got a switch for 9 bucks. All the ones I found that direct fit the trucks or so called military were 60 bucks and over. For 50 bucks I will put ends on my wiring.

 

[Suprman]

Nice you could probably solder leads onto the terminals and then seal over them with some epoxy or rtv.

 

[maccus]

Does the switch you got close its contacts at 60 PSI ? I would not solder wires to the existing contacts as you might melt the plastic. Causing a leak or just a bad contact. Use the correct wire connectors on the switch and a couple of short wires with Packard connectors on them.

I have replaced 3 of the switches like the one you have pictured with the pigtails. They all developed an air leak in the plastic area. Bad design I think.

 

[Floridianson]

Ok got around to getting the low air switch up and in. Just put the ends on the old wire and plug and play. Working as it should and yes it closes around sixty and opens below that. The switch is a N/0 switch so it will be open when there is air below 60psi. As said I got it at a hole in the wall truck parts place and there # was XFL FSC17491907 switch N/O. Don't know if that number will work anywhere else but a phone call to any truck parts place should carry a low air switch for around 10 bucks. Much better the 50 bucks.

 

[maccus]

That should work well I would think.

 

[Floridianson]

Yea working well enough for me. Yea I finished off after making the connection with liquid electric tape to seal the connection.

 

[Floridianson]

The switch is a N/0 switch so it will be open when there is air below 60psi.

I can't not correct my post but where it says, open when air is below 60psi. Should say closed when the air is below 60psi.

 

[Jbulach]

"Freightliner Kick-off Low Air Switch" - FSC-1749-1907 for $8 on ebay, going to give it a shot to replace mine that is leaking. Thanks Floridianson!!!