Viair constant duty

OhNoTheJiggies

New member
So I'm trying to install my viar constant duty with the 2.5 gal tank. Got the power wire ran and all the minor wiring done between the pressure sensor and the compressor. Everything's grounded. Tested the compressor and it works. But when I plug it into the pressure sensor and the power switch, nothing happens with a flip of the switch.
I haven't fully installed the switch/gauge panel(plan on installing it more cleanly than the provided panel). Anyway, the only thing I can think of being wrong is that the pressure sensor is broken. Any other ideas? Anyone have any clue as to how I could test the pressure switch to see if it's the problem? Maybe with a multimeter?
IMG_1485816516.611868.jpg


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JKU Arizona

Member
So I'm trying to install my viar constant duty with the 2.5 gal tank. Got the power wire ran and all the minor wiring done between the pressure sensor and the compressor. Everything's grounded. Tested the compressor and it works. But when I plug it into the pressure sensor and the power switch, nothing happens with a flip of the switch.
I haven't fully installed the switch/gauge panel(plan on installing it more cleanly than the provided panel). Anyway, the only thing I can think of being wrong is that the pressure sensor is broken. Any other ideas? Anyone have any clue as to how I could test the pressure switch to see if it's the problem? Maybe with a multimeter?



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Does your wiring look this this? Viair Wiring.jpg
 

Frydaddy

New member
Most pressure switches cannot handle the full load of the pump and need to be run through a relay. It seems viair has put a relay inside the pressure sensor? Either way, the switch is probably toast.
 

Frydaddy

New member
Terrific. Any idea if there's a way to check with a multimeter?
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like u/JKUArizona said, pop off the cover and start checking things. The internal wiring should be pretty close to this diagram.

pressure_switch_with_relay_big.jpg HBswitch.jpg

Check for connections on the whole circuit.
Set the Multimeter to ohms, and check across the "Pressure switch" Low resistance means it is tripped and calling for the compressor to turn on. check across the relay coil (the two black lines in this picture) there should be a low resistance in the tens of ohms. The contacts should be open at this point (red to white in the pic).

check for operation on the whole circuit
Now give power to the relay (red and black in the pic) when you touch the (purple) wire to 12v, you should hear the relay click. If not, check for 12V at the (white) output.

Narrow down the results.
OK, you got this far, disconnect the (purple) wire, and touch 12v to the (black) signal wire.
If the relay finally trips, the pressure switch is bad. time for a replacement. Amazon has all you need.
If the relay did not trip, the relay is hosed. You will have to wire in a replacement.
 

OhNoTheJiggies

New member
like u/JKUArizona said, pop off the cover and start checking things. The internal wiring should be pretty close to this diagram.

View attachment 241666 View attachment 241665

Check for connections on the whole circuit.
Set the Multimeter to ohms, and check across the "Pressure switch" Low resistance means it is tripped and calling for the compressor to turn on. check across the relay coil (the two black lines in this picture) there should be a low resistance in the tens of ohms. The contacts should be open at this point (red to white in the pic).

check for operation on the whole circuit
Now give power to the relay (red and black in the pic) when you touch the (purple) wire to 12v, you should hear the relay click. If not, check for 12V at the (white) output.

Narrow down the results.
OK, you got this far, disconnect the (purple) wire, and touch 12v to the (black) signal wire.
If the relay finally trips, the pressure switch is bad. time for a replacement. Amazon has all you need.
If the relay did not trip, the relay is hosed. You will have to wire in a replacement.

You sir, are a gentleman and a scholar! I will do this and then report back with what came of it, thank you very much!!


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Frydaddy

New member
Thanks again for all that info. The relay is toast. So I guess I'll have to fix that. Feel better knowing that it's bad and replacing it than getting a new one and then it not being the problem.
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Sweet, A relay is easy to replace! You can save some money and still use that same pressure switch. Should be easy to wire, just follow that last diagram I posted.
 

OhNoTheJiggies

New member
Sweet, A relay is easy to replace! You can save some money and still use that same pressure switch. Should be easy to wire, just follow that last diagram I posted.

So I replaced the relay, Everything is good to go! Finally! Thanks again for your help... I owe you a beer when we meet!


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Last edited:

hinrichs

Caught the Bug
Whats the pressure switch look like? little green thing with 2 prongs? (thats the type I used to use in my air ride days...if so they go bad kind of easily so I would get a spare)
 

OhNoTheJiggies

New member
Whats the pressure switch look like? little green thing with 2 prongs? (thats the type I used to use in my air ride days...if so they go bad kind of easily so I would get a spare)

Lol. I just edited the post to say it worked. Had a bad ground. My buddy tried seeing what was up and wallowed out the hole that I drilled for the ground. Tugged on a wire and heard a little rattle. Saw it and placed a fatter screw in and it's up and running!


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Frydaddy

New member
Lol. I just edited the post to say it worked. Had a bad ground. My buddy tried seeing what was up and wallowed out the hole that I drilled for the ground. Tugged on a wire and heard a little rattle. Saw it and placed a fatter screw in and it's up and running!


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Youre using a screw drilled into the body as a ground? wow... :grayno:
 
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