ARB Twin Compressor: Extra wire at switch loom connector?

[Yellow Cake Kid]

Hi,
I was installing an ARB Twin Compressor a few days ago and wondered why the switch loom connector has a 3-pin connector with two wires on one side and three on the other.

The wiring layout does not show the wires between the loom connectors and the Compressor, so I mocked up an illustration:

I did not take a photo when I was installing the compressor, and I could not find an ideal photo on the web to use.

Here's a photo just in case it helps:

I am hoping that someone knows the answer.

Thank you!

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[Duece McCracken]

Hi,
I was installing an ARB Twin Compressor a few days ago and wondered why the switch loom connector has a 3-pin connector with two wires on one side and three on the other.

The wiring layout does not show the wires between the loom connectors and the Compressor, so I mocked up an illustration:

I did not take a photo when I was installing the compressor, and I could not find an ideal photo on the web to use.

Here's a photo just in case it helps:

I am hoping that someone knows the answer.

Thank you!

https://www.jlwranglerforums.com/forum/threads/my-diy-portable-arb-air-compressor.50003/

This is the only diagram I have seen actually use it.

I was under the impression that the ARB twin is just 2 ARB singles bolted on a plate with common pneumatics.

As far as what the deal is with that wire, Im still not sure. If I find time, maybe I'll throw a meter on mine and see what it has on it both run and non run. None of the twin kits seem to use it directly. It is curious.

Would make sense that its a jumper between the two series pressure switches, unless the twins just have one. Gotta see a twin disassembled now, lol

 

[Terrymo]

I don’t have a direct answer. I wired my ARB twin with a Grimm Offroad replacement 3 wire harness that connects to the back of the ARB switch for a simple constant 12 volt on off switch. The back of the ARB switch looks like this. I’m not sure if that helps or just confuses things.

 

[Yellow Cake Kid]

https://www.jlwranglerforums.com/forum/threads/my-diy-portable-arb-air-compressor.50003/

This is the only diagram I have seen actually use it.

Hi,
Thanks for the information and the link. I can't imagine any reason to use the third wire at pin 2 when it is not connected to the compressor in the factory wiring instructions. I wonder, is it required if the "ignition" circuit is not connected?

I was under the impression that the ARB twin is just 2 ARB singles bolted on a plate with common pneumatics.

I agree that the Twin compressor is just two singles. The compressor assembly has two Red/Black pairs of wire, with one pair powering each single compressor.

As far as what the deal is with that wire, Im still not sure. If I find time, maybe I'll throw a meter on mine and see what it has on it both run and non run. None of the twin kits seem to use it directly. It is curious.

Would make sense that its a jumper between the two series pressure switches, unless the twins just have one. Gotta see a twin disassembled now, lol

I had considered the idea that the red and purple are "jumped" inside the connector, but it seems unlikely, as the connector moldings are relatively precise and are not meant for internal bridges, etc.

I believe the twin uses a single pressure switch after the air lines are combined. I could be wrong.

When I studied the wiring diagram in the supplied manual, I could not see any reason to connect wires to the switch pins 2, 6, or 7 unless you were using the Ignition or Dash Illumination features. It seems that pin 3 Hot and pin 8 ground would be sufficient to switch the compressor on and off. I could be wrong.

Thank you!

 

[dstevens]

I believe it is +12V from the compressor power supply. The compressor switches on when purple gets +12V, so is the supply for the switch. The other ARB configurations (air lockers etc) get their +12V from the ignition via a diode, so don't use the red wire. I'd double check with a multimeter.

 

[Yellow Cake Kid]

I believe it is +12V from the compressor power supply. The compressor switches on when purple gets +12V, so is the supply for the switch. The other ARB configurations (air lockers etc) get their +12V from the ignition via a diode, so don't use the red wire. I'd double check with a multimeter.

Hi,
Thanks for the information. This is starting to make sense. I guess the Black ground is just a safety ground, the Purple is a 12v "return" from the switch, and something needs to supply the 12vDC through the switch to the relay in the compressor assembly.

The source of the 12vDC could be the ignition circuit or a split from the compressor's main power supply.

Unfortunately, the install I did a few days ago has left the building, so to speak, and the compressor was buried in one of those slick onboard installs so it would be very hard to make any meaningful measurements without disassembly.

I should have answered the question before the assembly, but there was a time constraint.

I'd like to fully understand the details by the next time I am asked to work with an ARB Twin, and I would love to minimize the wiring bundle, as per the suggestions shown above, on installs that are not using lockers, etc.

Thank you!

 

[Left Field]

I believe it is +12V from the compressor power supply. The compressor switches on when purple gets +12V, so is the supply for the switch. The other ARB configurations (air lockers etc) get their +12V from the ignition via a diode, so don't use the red wire. I'd double check with a multimeter.

Agreed.

The red wire tests out showing it is tied internally to the +12V power to the compressor motors. It appears to be provisional and with their current wiring is not needed.

The purple wire is used for the pressure switch / motor control relay and is to be connected to a compressor on/off switch. It needs +12V to operate.

The black wire is a ground and is tied internally to the small ground wire in the motor power connector. It does not need to be connected (if the other small black wire is already grounded).

The lack of a wiring diagram for the compressor itself makes creating or modifying a control harness a bit challenging...

LF

 

[dstevens]

Using the aux switches I just connected purple and ignored the rest.

What gets me is that if there is a wiring diagram it shows pin connections with no hint about what is going on inside the component. eg for the switch we can guess that some of the connectors are for illumination but why should I have to probe the switch and test it out? Labeling the wires with a name as well as color would help.

 

[Duece McCracken]

This thread has shaped up nicely!!

 

[Yellow Cake Kid]

Using the aux switches I just connected purple and ignored the rest.

What gets me is that if there is a wiring diagram it shows pin connections with no hint about what is going on inside the component. eg for the switch we can guess that some of the connectors are for illumination but why should I have to probe the switch and test it out? Labeling the wires with a name as well as color would help.

If I understand correctly, you are saying that you used one of your Jeep factory option auxiliary switches rather than an ARB switch. The Jeep's aux lead supplies 12vDC directly to the compressor via the "purple" wire.

Thank you!

 

[dstevens]

That is my recollection - just wired one aux to purple. I installed the compressor under the hood and ran the air line out to the bumper so I never have to open the hood in order to air up. Just hit aux and connect the air line.

With the twin ARB I can usually be on my 3rd tire before the other guys have their portable compressor connected to the battery and running. Except they have learnt to park next to me so that once I finish my tires I can work on theirs too. Typically I air up 10 tires each time.

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