air pressure switch on endless air

[nathanzook]

ok i got an endless air set up off and air con compressor, atm i have a toggle switch set up to engage the clutch on and off, iv bought an arb prssure switch and they said in need to put a relay in or ill burn out the switch which i have no clue where to start, if any one could do a diagram for me that would be great, basically i want a main switch to turn the system on and then the pressure switch to work as needed.
any help would be great!

thanks

[ledgend80]

i am guessing you want something like this

fused batt power to 30
ign power to switch then to pin 86
from pin 85 to pressure switch and then to ground
then from 87 to compressor (could be 87a can't remeber off the top of my head)

[-Scott-]

Do ARB understand that it's an engine driven compressor, and you're only switching the clutch, not a motor?

How much current does an a/c clutch draw? I would've thought an average pressure switch would switch an a/c clutch without drama - don't most a/c systems have a pressure switch in the receiver/dryer in line with the clutch?

[nathanzook]

yea they know is on an air con compressor and yes ac system has a pressure switch but its not right (cut in an out) they specifically said 'you will need a relay for that application.' and they arn't really cheap to just wire and try at $60 each lol, not sure of the current draw atm but i'll have a look, they told me the switch is 5amps

[Pops]

Hook in a relay as Legend80 suggests as a relay is really cheap.

[bushy555]

I'd highly recommend NOT to do a quick dodgey like I did and just wire it direct to battery via a switch mounted under the bonnet.
It makes way more sense to wire it via the ignition anyway; stating the dead set obvious - the engines gotta be going for it to work.
I just pulled the hose off, forgot to turn the switch off, and turned my Brumbys ignition off. Two days later, not having driven it, battery was completely dead.

The below *should* work. If it doesn't first point of call is to just check if the relay has a diode or two for spike protection.
Might just need to reverse 30/87 and/or 85/86 depending on if one or both lines are protected or not.
LED on the left mounted on the dash will tell you when you've got the switch turned on. LED on the right mounted on the dash will tell you when the compressor is actually running.

[ledgend80]

I'd highly recommend NOT to do a quick dodgey like I did and just wire it direct to battery via a switch mounted under the bonnet.
It makes way more sense to wire it via the ignition anyway; stating the dead set obvious - the engines gotta be going for it to work.
I just pulled the hose off, forgot to turn the switch off, and turned my Brumbys ignition off. Two days later, not having driven it, battery was completely dead.

The below *should* work. If it doesn't first point of call is to just check if the relay has a diode or two for spike protection.
Might just need to reverse 30/87 and/or 85/86 depending on if one or both lines are protected or not.
LED on the left mounted on the dash will tell you when you've got the switch turned on. LED on the right mounted on the dash will tell you when the compressor is actually running.

good idea with the led but would it not be better to position the led that is on the right of the pressure switch to the wire that comes out of 87. this way you know when the clutch solenoid has power going to it. then you could tell if you have a faulty relay. still the same as you have suggested just a different way to get the same outcome.

[bushy555]

Well spotted. Fixed.

[nathanzook]

thanks guys