Bedside compressor help

Hey TW, got a few questions.

So I wired up a fuse block to the bedside compressor mount, I did this so I could run my rock lights and rack lights here instead of having a ton of wires running to the front of the vehicle.

I ended up using about 25’ of wiring so it called for something around 4ga wire for the amperage I was expecting, unfortunately the fuse block connections are much smaller so I had to improvise.

Ran everything and crimped all of the connections correctly, but I’m not getting any power to the fuse block.

I’m also guessing that the ground I have isn’t adequate, but I shaved off all powder coat as you can see.

 

Time to get out the multimeter. Is your mount properly grounded? Do you have power through the 80A fuse? What is the connection on the top of the fuse block, 12vdc?

 

I would start with that ground. What you have wired up is not adequate. Would be best to run that ground back to the battery, or the engine block. The frame might be ok to ground to but you would be putting a lot of power through the small grounding wire that goes from the body to the frame.

 

Its always a good idea to run a dedicated NEG lead back to the battery for larger loads or distribution blocks like this.

Ive never seen one of those compressor mounts in person, but if it just mounts to the composite bed, then its not touching any metal and wont be bonded to the chassis for your negative.

 

This is the fuse block I used.

$14 SOYOND 12 Volt Fuse Block, 6 Way Marine Fuse Block with Led Indicator Damp-Proof Cover 6 Circuits Fuse Box with Negative Bus Fuse Panel for Car Boat RV Truck Dc 12/24v

https://www.amazon.com/dp/B07HDZVW3P/ref=cm_sw_r_cp_api_glc_fabc_FQ42FbVW75497?_encoding=UTF8&psc=1

Yeah I’m waiting for my buddy to return my damn multimeter or I would’ve eliminated a lot of troubleshooting yesterday.

 

Yeah it just mounts to the bed, that makes sense, I was thinking it was probably the ground. Damn, didn’t want to have to run another one back to the battery.

 

The grounding wire is 4ga, the same as the positive running to the battery

 

This is your problem. The bedside cubby metal box you are grounded to just screwed into the composite bed, which is non-conductive and non-grounded.

 

For testing purposes, take your jumper cables and clamp 1 end on that ground stud and the other end on your bumper bracket.

 

Oh okay, I thought a piece of metal was adequate enough, as you can see I’m no electrician haha

 

Just to clarify, you’re saying take the negative of a jumper cable and put it on the negative of the fuse block, and then take the other negative cable and put it on the bumper bracket? Didn’t even think of that, that’ll tell me my issue rather quickly

 

Yes, just holding a wire to your ground and holding it against a clean spot on the metal frame, bumper bracket, etc will let you know if the only issue you are having is the missing ground.

 

Well that didn’t work, now I’ll try and run a long piece of wire to my negative terminal and see if that works.

 

Go smack your buddy and have him bring it back sooner This will save you a bunch of time troubleshooting.

The connections at the battery LOOK ok, but without being there and having a multimeter, I can't diagnose over the internet...

The fusable link looks fine, the wire connection to the battery and such looks fine.

I would focus on the fuse block and double check your fuse(s).

 

I did something similar but like everyone said, run a ground wire directly to the engine bay.

Personally, I used a 50a circuit breaker in the engine bay, ran 4ga power and ground cables to the driver bed cubby, then I used a distribution block like

$24 Rockford 1/0 Awg Distribution Block

this one from Amazon for the power cable (one end goes into my bluesea distro block to power accessories) and the other directly to my compressor. I'll almost never use my accessories when my compressor is on so I won't draw too much power at once.

 

I appreciate the help man, so I realized you can’t get a close-up of the fuse block, this is what I’m worried about: the ring terminal on the fuse block is quite small and doesn’t cover the entire ring connector from the wire, and I didn’t know if they made smaller ring connectors for 4ga wire.

 

For the purpose of troubleshooting that wont matter, but in the long run youll want to replace it with one of these when you make the run up to the battery. Probably #10 or 1/4"
https://crimpsupply.com/compressionlugs?terminal_wiresize_range=1789

 

Oh this is exactly what I was looking for! Had absolutely no idea they made these for this big of a gauge, you’re a lifesaver

 

Any reason why they’re so pricey? $7 a pop seems a little steep for lugs