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Pressure switch wiring for OBA

1

1996cc

NAXJA Forum User
Location
Springfield, OR
Everything I have read simply says supply 12v power to the switch (fused of course), then from the switch to my AC compressor. My pressure switch has 3 wires going in and 3 coming out. One on each side is ground, which ties into the metal body of the switch. I cut those because it is now grounded through the mounting bracket screwed to the fender well. I disconnected the two top leads. Now I have 12v going in on the line side (white wire with red connector), and the brown wire is going out to the compressor.

Not that it is going to help much, but here is a pic:

DSC03672.jpg


Long story short, as soon as I install a fuse and turn the switch to "auto" from off, it blows the inline fuse (tried 15, then 30amps). Doesn't matter if the jeep is running or not. So that exhausts my electrical knowledge. Anyone have any ideas? How did you wire yours?

Man I hate electrical crap!!
 
is the line coming out of your compressor loaded or unloaded when it's blowing fuses? if it's got pressure on the compressor when you try to kick it on, it'll require more power than it would unloaded. I donno, just a thought.
 
I haven't gotten it to work yet, so there is NO air pressure in the system anywhere. Good thought though.

And isn't an AC compressor always pressurized anyway??
 
dzraces said:
sounds like one of your grounds has direct power to it and not switched through the pressure switch.
Click to expand...

Could you explain this a little more, I don't understand electrical very well. How would a ground have power to it??
 
1996cc said:
I haven't gotten it to work yet, so there is NO air pressure in the system anywhere. Good thought though.

And isn't an AC compressor always pressurized anyway??
Click to expand...


No, i have an unloader on the pressure line. Use a check valve/unloader combo valve and its a lot easier to start the compressor and doesn't blow my fuses.
 
1996cc said:
Could you explain this a little more, I don't understand electrical very well. How would a ground have power to it??
Click to expand...
If one of the 2 grounds isnt a ground but a switched path to ground and you have now given it a direct path to ground instead of running it through the switch it would explain the excess curent draw
 
dzraces said:
If one of the 2 grounds isnt a ground but a switched path to ground and you have now given it a direct path to ground instead of running it through the switch it would explain the excess curent draw
Click to expand...

One ground comes from the line in wire (formaly from the wall plug) and screws to the switch body. The the other wire (also screwed to the switch body) goes out to the motor wire. Could the switch be connecting to the switch body directly internally (that I can't see) to do as you describe??
 
A) you don't need an unloader with a engine driven compressor( the A/c compressor can handle lots of pressure on startup)
B) go get a Viar pressure switch that loads at 70psi and unloads at 110psi or somewhere around there. One wire in(power) and one wire out( to the compressor clutch.)

here is the one I bought from this same guy:

http://cgi.ebay.com/ebaymotors/VIAI...tegoryZ33586QQihZ012QQitemZ220043998051QQrdZ1
 
Are you sure the wires you cut off are the ground connections? Or did you tie the hots into the ground connections?

A blown fuse indicates a short to ground.

Break out your DVMM and start tracing.

Rev
 
1996cc said:
This is a cheap jeep, i.e. use what I have for free. I want to make this work with what I have.
Click to expand...

That pressure switch is only 9.95.......that seems pretty cheap for a lot less headache.
 
Try hooking the white wire in line (to the screw directly obove the brown wire) with the brown wire. Thats how I hooked mine up, though my switch is a different brand than yours. You don't need both sides of the switch.
Mike
 
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