M939 Air pressure switch

[rcb]

Greetings: Anyone know who sells the air pressure switch for
the 900 series air tanks ? My 923 was missing the one on the
top tank.
Thanks...
Bob

 

[Csm Davis]

Not sure who makes them new but I can get you one used.

 

[rcb]

Works for me... how much and where do I send $.
Thanks much !!!
Bob

 

[M35A2-AZ]

Erik's has them. P/n
12375453
Low Air Pressure Warning Switch For M939 Series, 12375453 / 11669414-1

 

[juanprado]

There is 2 styles but they work the same. There is one older air switch with the connector on the metal can like the picture from Erik's and the newer style has a short pigtail with the connectors and it is a little narrower.

How did they keep the buzzer and light from sounding? bypassed? or was it just robbed off the lot?

Good luck!

 

[juanprado]

The picture of Erick's and my reference was to the the low air pressure switch on the air tank. There are 2 air tanks on the passenger side and each one has a low pressure air switch that activate the buzzer and the warning light if low air pressure.

On the dash there is a spring brake override control valve with a large black knob. The air valve is plumbed with an air line but it also another pressure switch ( different than the other 2) that lights the spring brake light on the dash light cluster over the steering wheel. If you are missing that then you need a valve, knob, and switch. Check out the tm's available here on ss. There is a 2 parts manual and a 4 part repairs tm downloads.

It also sounds like your light switch is bad. There is also a tm for the basic driver's manual that covers the operation of the light switch and the brake override valve along with all the basic info.

 

[Csm Davis]

Help are you talking about a 5 ton 939?

 

[Dukeman]

yeah apparently I have the newer style according to Juanprados post. It has pigtails. It is leaking right at the base and I can't find that style anywhere.

 

[juanprado]

air pressure switch

check the classifieds. I believe there is one posted but mis-identified as an oil pressure switch. My oil pressure switch is one wire and a larger bell type can than this photo.

http://www.steelsoldiers.com/parts-sale/96094-oil-pressure-switch.html
My air pressure switches on the air tanks look like these.

Good Luck!

 

[Dukeman]

Awww, looking out for me Juan, thanks!

 

[jcollings]

There is 2 styles but they work the same. There is one older air switch with the connector on the metal can like the picture from Erik's and the newer style has a short pigtail with the connectors and it is a little narrower.

How did they keep the buzzer and light from sounding? bypassed? or was it just robbed off the lot?

Good luck!

You said the sender from Eriks is the old style, On Eriks site it says it's the new style? so which is it, I have a 1990 923a2
with tails on it, Leaking

 

[simp5782]

You said the sender from Eriks is the old style, On Eriks site it says it's the new style? so which is it, I have a 1990 923a2
with tails on it, Leaking

NSN 5930011890494

Your truck has two of them.

 

[jcollings]

Does it matter which one the can type or the tail type looks like the tail type would work better imo.

 

[Floridianson]

You can go to any truck parts place and ask for one cheap. Yes you will have to rework the wires but easy fix.
NAPA carried trucks parts at one time.

 

[jcollings]

The ones from any truck place do they have the Packard ends connection for wire hookup?

 

[Floridianson]

Yes Packard spade ends so small pig tail is what you will make up.

 

[jcollings]

Hey thanks

 

[Floridianson]

http://www.steelsoldiers.com/showthread.php?139694-M939-low-air-switch

 

[bigsix]

Guys this info has helped me very much. thanks to yall.

 

[TEAMJENSEN]

My low air pressure light and buzzer would intermittently light and sound although the pressure in both tanks read 120psi. I checked the voltage from cab to switch and reads 12 volt. The ground tests good but I still scraped and wire brushed ground boulders and frame and still no luck. I checked voltage across both switches and they are good when truck pressure is good. I even went and replaced both switches with new ones from Erik's, who by the way is very helpful. Now the light and and buzzer went from intermittently to sounding constantly.....driving me crazy. The voltage across the switches is good to the ground. Any thoughts? Your help is greatly appreciated!!!!

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