ARB Dual air compressor shorted out.

[chorky]

I was more referring to the burnt up wire with the green on it. Thats usually a good indication of corrosion which causes higher resistance. I have seen A few wiring harnesses from various companies that were corroded under the plastic shielding and being brand new

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[Minty JL]

can't catch a "break." Ill pretend you did that intentionally and I'll say - I see what you did there.

to be fair, the braking issue was a result of my taking the compressor out to inspect it.

I'm sure that was the intent

 

[sharpsicle]

I'm so confused how ARB is saying that using a different switch caused a wiring meltdown. That does not make any sense at all. A switch is a very simple device, and it doesn't cause meltdowns by itself. Is there something goofy with how their relay is working or something? Are they claiming that your AUX switch somehow forced current through their wires?

I mean hell, what's to stop you from taking it out and saying you never used the AUX switch anyway? This 100% feels like a avoidance technique more than anything else.

 

[Edub]

I'm so confused how ARB is saying that using a different switch caused a wiring meltdown. That does not make any sense at all. A switch is a very simple device, and it doesn't cause meltdowns by itself. Is there something goofy with how their relay is working or something? Are they claiming that your AUX switch somehow forced current through their wires?

I mean hell, what's to stop you from taking it out and saying you never used the AUX switch anyway? This 100% feels like a avoidance technique more than anything else.

I think because the short seems to come from the switch itself. I'm confused on that one too.

you can see that the ground wire on the switch side (smaller harness) is also melted.

My thing is (as you said as well), the aux switch is (aux4) is such low amps that theres no way it could have caused this.

 

[Edub]

I was more referring to the burnt up wire with the green on it. Thats usually a good indication of corrosion which causes higher resistance. I have seen A few wiring harnesses from various companies that were corroded under the plastic shielding and being brand new

The rep that I spoke to also pointed this out, but... isn't that also due to a faulty wiring harness?

The compressor was tucked away behind the wheel well, the harness itself separated from the engine by the master cylinder. That couldn't have been due to heat. Heck, Even ARB sells a mounting kit to place the compressor far closer to the motor then what this was.

 

[chorky]

The rep that I spoke to also pointed this out, but... isn't that also due to a faulty wiring harness?

ok so question. The left side of that picture where it is coroded and melted. Is that the compressor side of the harness? I believe so but want to verify….

^^^ this is exactly my point. If the rep also pointed it out, then why wont they honor a warranty? Connecting the purple wire on the harness to your aux switch (if done correctly using adhesive heat shrink) instead of the battery wouldnt cause water intrusion on the compressor side of the harness. And if it did it would take quite some time, like a couple years probably, for moisture to wick all the way up a wire, through a connector and into the compressor side of the harness. And even then i would expect to see the side that you cut to hook to the aux switch to be corroded long before the compressor side.

to me there seams to be something going on that ARB isnt talking about. That corrosion being on the compressor side of the harness is either from a poorly made harness or water got inside the connector itself (which is supposed to be waterproof), and wicked itself up.

i would be very careful as you take it apart to not disturb much. That way you can see how those wires terminate inside the compressor. Given the mounting location so close to constant road spray, it is possible that if the wires terminated at the compressor side are not ‘waterproof’ then corrosion could have started there.

 

[Rockabillyroy]

one thing I did find while inspecting the negative wire was the terminal used for the negative cable didn't seem to be crimped properly. but this could also be a result of the heat. thoughts?

Would the heat have been hot enough to melt away any wire crimped inside? Clearly there had to be a connection of some sort or else it never would have worked, and I've been using it for over a year.

I think those come without the ring terminals installed. If so, do you know who crimped those?

 

[dbongard]

Hey guys,

Grimm Off-Road is very careful in their installation guide to make sure that you connect the switch correctly. They even highlight the direction of the arrows because this is so important.

If you plug those wires on in the reverse order (i.e., PURPLE - RED - BLACK) then when you turn your switch on you will be directly shorting your power supply wire (the RED) to the thin control ground (BLACK).

i.e., switch ON closes these two contacts:

The burnt wire shown (the BLACK) is ONLY provided as a ground for your switch illumination LED's. It carries only milliamps even when both LEDs are lit, and those LEDs are capable of less than half an amp at full short before burning to open circuit. When connected correctly no such damage could have occurred. However, when the switch wires are connected backwards and shorted to RED across the switch contacts instead, the switch is capable of passing 20 amps to it and doing exactly the damage you see in the pics.

A simple but costly error.

PLEASE WIRE RESPONSIBLY

 

[Rockabillyroy]

Hey guys,

Grimm Off-Road is very careful in their installation guide to make sure that you connect the switch correctly. They even highlight the direction of the arrows because this is so important.


If you plug those wires on in the reverse order (i.e., PURPLE - RED - BLACK) then when you turn your switch on you will be directly shorting your power supply wire (the RED) to the thin control ground (BLACK).

i.e., switch ON closes these two contacts:

The burnt wire shown (the BLACK) is ONLY provided as a ground for your switch illumination LED's. It carries only milliamps even when both LEDs are lit, and those LEDs are capable of less than half an amp at full short before burning to open circuit. When connected correctly no such damage could have occurred. However, when the switch wires are connected backwards and shorted to RED across the switch contacts instead, the switch is capable of passing 20 amps to it and doing exactly the damage you see in the pics.

A simple but costly error.

PLEASE WIRE RESPONSIBLY

He used the factory aux.

 

[sharpsicle]

Hey guys,

Grimm Off-Road is very careful in their installation guide to make sure that you connect the switch correctly. They even highlight the direction of the arrows because this is so important.

If you plug those wires on in the reverse order (i.e., PURPLE - RED - BLACK) then when you turn your switch on you will be directly shorting your power supply wire (the RED) to the thin control ground (BLACK).

i.e., switch ON closes these two contacts:

The burnt wire shown (the BLACK) is ONLY provided as a ground for your switch illumination LED's. It carries only milliamps even when both LEDs are lit, and those LEDs are capable of less than half an amp at full short before burning to open circuit. When connected correctly no such damage could have occurred. However, when the switch wires are connected backwards and shorted to RED across the switch contacts instead, the switch is capable of passing 20 amps to it and doing exactly the damage you see in the pics.

A simple but costly error.

PLEASE WIRE RESPONSIBLY

Yeah, but we aren’t using the switch at all, and the purple wire is the only one getting sent current. I get what you’re describing but that’s not what’s at play here.

 

[dbongard]

Yeah, but we aren’t using the switch at all, and the purple wire is the only one getting sent current. I get what you’re describing but that’s not what’s at play here.

Shout out to our Melbourne engineer, Sam, on this one.

The fact that the installer un-necessarily grounded the switch wire...

...actually means that once the main termination broke at the battery, the compressor motors would then be trying to complete their circuit to ground by using the thin BLACK @ 80 amps which would have fried it. (i.e., the thin black and the motor ground BLACK-WHITE STRIPE were connected but NO LONGER connected to the battery).

If not using the switch then the ground in the ARB switch terminal should have been left un-connected.

 

[sharpsicle]

Shout out to our Melbourne engineer, Sam, on this one.

The fact that the installer un-necessarily grounded the switch wire...

...actually means that once the main termination broke at the battery, the compressor motors would then be trying to complete their circuit to ground by using the thin BLACK @ 80 amps which would have fried it. (i.e., the thin black and the motor ground BLACK-WHITE STRIPE were connected but NO LONGER connected to the battery).

If not using the switch then the ground in the ARB switch terminal should have been left un-connected.

Ah ok, that makes a lot more sense. The other post only talked about reversing the wires on the switch, but this explanation really ties it together. Thanks for the clarification.

I’m still concerned that ARB is saying that if their switch isn’t used that there’s no warranty, even if you hook it up right to the AUX switch in the way you described.

 

[Rockabillyroy]

Shout out to our Melbourne engineer, Sam, on this one.

The fact that the installer un-necessarily grounded the switch wire...

...actually means that once the main termination broke at the battery, the compressor motors would then be trying to complete their circuit to ground by using the thin BLACK @ 80 amps which would have fried it. (i.e., the thin black and the motor ground BLACK-WHITE STRIPE were connected but NO LONGER connected to the battery).

If not using the switch then the ground in the ARB switch terminal should have been left un-connected.

So every grimm kit that uses their harness is wired incorrectly?

 

[JTR178]

Did you have the main harness directly connected to the battery?

I did. both negative and positive. confirmed.

one thing I did find while inspecting the negative wire was the terminal used for the negative cable didn't seem to be crimped properly. but this could also be a result of the heat. thoughts?

Would the heat have been hot enough to melt away any wire crimped inside? Clearly there had to be a connection of some sort or else it never would have worked, and I've been using it for over a year.

And it reached the negative terminal without any issues? From Innovative AT Products install instructions they state on page 9 to use the ground stud on the fender because the ground wire won't reach the battery. I'm wondering if added stress is what caused your terminal crimping to fail.

Edit: but if running the cable from a different direction (fender vs interior) it may not be an issue. I don't remember the difference in length between the cables, if any. Just food for thought I guess.

Edit to the edit: I used Aux-4 and did not use the switch grounding wire from the ARB harness that you did. (Page 7 on linked instructions above)

 

[Edub]

And it reached the negative terminal without any issues? From Innovative AT Products install instructions they state on page 9 to use the ground stud on the fender because the ground wire won't reach the battery. I'm wondering if added stress is what caused your terminal crimping to fail.

Edit: but if running the cable from a different direction (fender vs interior) it may not be an issue. I don't remember the difference in length between the cables, if any. Just food for thought I guess.

Edit to the edit: I used Aux-4 and did not use the switch grounding wire from the ARB harness that you did. (Page 7 on linked instructions above)

So there are two harnesses on the compressor. A large one that runs to the battery, and a smaller one that runs to the switch (and locker switches if installed). On the smaller end, I had grounded to a stud in the engine bay near the driver side wheel well. The larger harness has two negative cables (one small and one large). those both run to the negative terminal on the battery.

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