ARB compressor connection

[rollingpinz]

Hello

I’m installing an ARB compressor and the on/off switch needs to be wired to an accessory tab and a dash light tab. I don’t care about lighting the switch, but can someone recommend a connection that is only active while running?

[rmel]

Circuit breaker #10 is switched via Ignition. But that has at least two
connections on it already for the Carb solenoids, Blower motor, and
Wiper. The other circuit is terminal #16 on the ignition switch which
provides power to the ignition coil/RPM limiter, this is not a protected
circuit per se. So if used fuse it otherwise a short will bring you down.

I'd suggest you tap off of the Auxiliary power outlet under the dash on
the far left side. Fed by Breaker #12. It's a "Hot" circuit when the Ground
switch is closed. It also gives you a convenient place to mount the switch.
The draw for the ARB switch should only be the current to the power
relay so it's pretty low.

[rollingpinz]

Thank you

[rollingpinz]

Hello

Follow up question. You mentioned a power relay. Is it possible for this relay to be 12 volts? There is a fused(5amps) wire that goes to the negative terminal of battery #2. I thought maybe the light in the included switch, but the writing on the switch says it’s good for 12 as well as 24 volts.

My plan is to use the switch for the power outlet since the power outlet isn’t connected, the switch is already mounted, and not used for anything else. Win-win.

[rmel]

I have been assuming your doing a fresh install of a onboard 24V Single or Dual ARB compressor.

These come with a wiring harness (see attached). That harness includes a Bosch type relay and
an inline fuse that will provide power to the compressor WHEN then switch is turned on. I have
one installed in my 710K however, it is all powered off of my 12V auxiliary battery. The compressor
and the relay are both powered from 12V.

I have been assuming, and this may be incorrect that your installing a 24V onboard compressor
with all it's factory embellishments -- maybe your not? It sounds like there's already some bits
and pieces in place e.g.e #2 battery connection -- what's that exactly?

So before I go any further, can you tell us what ARB model this is and what may or may not be
in place already

ron

Screenshot 2025-01-12 at 7.39.38 AM.jpg (257.57 KiB) Viewed 565 times

[rollingpinz]

Hello

I’m installing the twin motor 24 volt compressor. It has two looms. One goes to the batteries. It has two large red wires that connect to positive on the #2 battery, one large black wire that connects to negative on the #1 battery, and a small black wire with a 5 amp fuse that connects to negative on the #2 battery.
Then there is the switch loom. It has a red/yellow wire and a blue/white wire (diodes on each wire)that connect to a 24 volt source. It connects to the switch and connects to a long extension that connects to the compressor.
I was hoping to skip the arb switch. I was thinking that I could splice in the diode from the red/yellow wire to the long extension and use the switch for the pinzgauer power outlet socket.
I think the blue/white wire is just for the light in the switch.

[rmel]

OK, this helps a lot! Yes, you could set it up that way -- using the AUX power switch under the dash.
I did something similar. Just a suggestion, I also added a small Air tank as a reservoir to help buffer
the compressor.

[rollingpinz]

I had been reading about others putting a tank for the same reason. Some questions though. Doesn’t it require a pressure switch to turn off the compressor when the tank is full? Otherwise, if you just have a large open volume inline with the hose, doesn’t that reduce volumetric efficiency? How big a tank do you have?

[rmel]

Ya know! The one thing I don't like about the electrical setup is
the negative connection for the Solenoid -- the fused BLK wire.

What is less than optimal is that you can turn the Solenoid (relay) ON
even with the Ground switch open. IMHO ARB went the El Cheapo using
a 12V relay on a 24V application. I didn't run into this issue with my fit
up as I went 12V via my Auxiliary power, so I didn't think about this until
I realized they are using a 12V relay.

So keep that in mind. A wee bit of nit perhaps, but y'll just have to
remember to keep that switch off otherwise there will be some leakage
on the top battery. Ya, going with a Switched circuit instead would make
that less apt to happen.

If you want to eliminate that issue, another approach I'd probably take if it
were me, is to put the fused BLK on the Neg terminal of the bottom battery
then run the Red-Yel line to the center point for a 12V source, then the
Battery GND switch protects you but you will then need to run that 12V line
to the switch and that Red-Yel should be fused but both fused is OK too.

There's always something that needs to be compromised

With respect to the air reservoir, I went with what would fit, a 1/2 gallon Viair
tank. My thinking was as a buffer but also at times I'll put a air gun on the end
and give the cab a "blast" to blow out dust, there's enough air in that tank for
about 1 to 2 seconds. The other reason is if I break a bead on the trail and
need a bit more higher pressure air to help pop the bead.

[rollingpinz]

One more question. What’s with the diodes on the red/yellow and blue/white wires? I’ve heard of voltage dropping diodes. Is that what these are?
Also, thank you so much for your help

[rmel]

These are isolators to prevent back current, under certain circumstances.
Not necessary if everything was 12V or 24V but they have a mixed solution
here, so a bit of protection. The forward voltage is going to be approx. 0.7V.