ARB Compressor not switching on

[georamorim]

Hi all, I have an ARB twin compressor that I have been using for 2 years flawlessly. I went to air up today and the switch did not turn the compressor on. I've checked fuses and all is good. I've checked for power to the compressor and nothing seems off there. The light on the switch illuminates when I turn on the head lights, so there's at least that power going to the switch, but turning the switch on does nada. Any troubleshooting tips or possible solutions?

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[heftysmurf]

I've not had an ARB in quite some time but if I remember, at some point in that wiring, there is a relay -- swap that out?

 

[cranbiz]

Verify that you have 12V to the compressor when the switch is on. If it is there, there is something wrong with the compressor. If not, carefully check your ground ( a bad ground may appear to have power but once a load is on the circuit, it fails) and verify the relay is switching. It's a standard Bosch style relay and readily available if needed. If you use the compressor a lot, go ahead and replace the relay anyways. The contacts do arc over and pit making the connection poor. The relays are cheap.

 

[Steven_B]

Double-check that you have power to the compressor from the switch (trigger wire). The twin compressor uses a separate relay for each compressor, so the likelihood that both went out at the same time would be rare. However, ARB had a bad batch of relays a few years ago that were grey so anything is possible. The pressure switch is also a possibility and would prevent both compressors not turning on. However, I have only seen a handful of pressure switches fail over the past 20 years.

Are you sure that both motors were running in the past? It's possible that one stopped working a while ago and the second just stopped (bad batch of relays).

 

[georamorim]

Verify that you have 12V to the compressor when the switch is on. If it is there, there is something wrong with the compressor. If not, carefully check your ground ( a bad ground may appear to have power but once a load is on the circuit, it fails) and verify the relay is switching. It's a standard Bosch style relay and readily available if needed. If you use the compressor a lot, go ahead and replace the relay anyways. The contacts do arc over and pit making the connection poor. The relays are cheap.

Thanks. Where is the relay? I don't see anything that looks like a relay.

 

[Oak]

I've not had an ARB in quite some time but if I remember, at some point in that wiring, there is a relay -- swap that out?

It's actually a diode that allows power to go one way. If it's bad or backwards the unit won't turn on. You will feel it in the wire. Very inexpensive to replace if bad.

 

[alextremo]

Had the same thing happen to me. Took it apart, did the troubleshooting from their website, replaced the pressure switch and couldn’t find anything and still didn’t work. Reinstalled with the original pressure switch and it worked for a couple months, this weekend had the same thing happen again. Frustrating.

 

[Steven_B]

Thanks. Where is the relay? I don't see anything that looks like a relay.

They are located under the metal heatshield as well as the PSI switch.

 

[cranbiz]

I don't have an ARB twin, just the CMKA12 and the relay was in the main power line, after the fuse holder and was triggered by the harness that went to the switch/switch bank.

 

[georamorim]

Thanks all for your advice and tips. I followed them and did some tests to find out that there was no power going to the switch. Im back in bidness. Thanks all!

 

[teamblkdog]

Thanks all for your advice and tips. I followed them and did some tests to find out that there was no power going to the switch. Im back in bidness. Thanks all!

Found this old thread trying to gather info prior to troubleshooting my ARB twin that just stopped working. Are/were you using a factory AUX switch? You mentioned the light on the switch was working, but you stopped getting power to it. Just curious your troubleshooting process.

 

[georamorim]

Found this old thread trying to gather info prior to troubleshooting my ARB twin that just stopped working. Are/were you using a factory AUX switch? You mentioned the light on the switch was working, but you stopped getting power to it. Just curious your troubleshooting process.

It was as simple as a fuse. Replaced it and tada.

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