Power and relay question for hardwired portable air compressor I

Hey all,

I am looking to hardwire a 12V Portable air compressor in the bed of the truck. I ran 6AWG battery/Welding Cable from the battery to the rear passenger side cubby box (approx 15-20ft). I have a short 2 foot 6awg cable grounded to the frame in the back as well.

50amp Circuit breaker 10'' off the battery inline on the power cable.
Add a fuse to a cab switch with 10awg wire ran to the cubby as well.
(I also have Aux Beam switch box I could use)

The compressor I had was an alltop 12v portable single compressor off of Amazon, 7CFM pulling 45amps. I removed the alligator clamps and wired it to the 6awg in the back with Anderson plugs. This gave me straight power but I wanted the ability to have it ignition switched on and off from the cab and have a pressure switch for auto shut off.

The 10awg wire from the switch ran to one side of the pressure switch and the other side of pressure switch ran to an 80amp relay on pin 85.

Pin 86 ran to a small wire coming from the compressor motor ( three wires total coming from motor. Positive, Negative, and small black wire which I think is either a ground cutoff switch wire or maybe thermal cutoff) (I believe the compressor works off a ground side switch)

pin 30 was connected to the 6awg positive wire. Pin 87 ran to a 50 amp circuit breaker then the positive wire on the compressor motor.

The system worked great for about 6months. The other day the compressor would not turn on and the relay would just click rapidly.

So either my wiring is facocked, or the compressor took a dump. I tested the relay and its works via 9v battery. I also tried swapping the relay with a new one and same thing happened.

So after that novel of a backstory.

1. Should the relay be upfront near the battery and I run the power from there back to the compressor. (would look like this. 12v switch (cab or aux beam) ---> pressure switch on compressor. Then 10awg from other side of pressure switch pin 85. pin 86 ground. 6awg (battery) ----> circuit breaker (50Amp) ----> pin 30. Pin 87 6awg wire to fuse (50amp) to back of truck positive compressor motor. (the third little black wire is what's throwing me off).

In the switch would power the pressure switch then that would trigger the relay and let the power flow through the relay. (don't know what to do with the third little black wire. I guess leave it on the switch on the compressor and just leave it in the "ON" position)

2. Repeat my current setup and chalk it up to a bad compressor (maybe the cylinder froze in the cold weather?)

3. Run my switch in the cab as a ground side switch and leave the relay that comes on the air compressor.

I feel like the more I look into this the more confusing it gets LOL!!

Any help would be greatly appreciated. Thanks Joe

 

I have my relay and fuse in the engine bay with a pressure switch on my air tank and a switch in the cab in case I don't want the compressor running

 

Yea I feel like I should have the relay in the front by the battery on the switch so I don’t have a live wire running to the back of the truck.

Does your cab switch run to pressure switch on the tank then back up to the relay?