Another Newbie to the site looking for an answer! Fuse for air compressor?

[gjk50003]

The wife and I bought a 2015 Chevy 2500HD Duramax to tow our travel trailer around the country, love the truck but it rides like a real lumber wagon while towing! I installed some Airlift bags under the rear end, an air compressor under the cab and went searching for a fuse to connect to. Pulled almost every fuse over 15 amps from under the hood, flipping the key off and on while testing power. Finally found a 15 amp that was hot only while the key was on and connected to it, the compressor worked!
Now my truck wont start, and my scan tool is not communicating! I saw one guy say the the OnStar module disabled everything. Could that be the case?
Thanks!

 

[ZeroGravity58]

Why are you looking for a 15amp fuse? You should be running a relay that connects to the battery. The only thing you need to tap into the fuse box for is a trigger for the relay.

 

[gjk50003]

Why are you looking for a 15amp fuse? You should be running a relay that connects to the battery. The only thing you need to tap into the fuse box for is a trigger for the relay.

The Airlift kit says to connect to a fuse, they supply a special connector to do so. I called OnStar and they say their system won't do anything to imobilize the truck without a subscription.

 

[gjk50003]

I'm going to disconnect negative battery cables and see if that'll reset everything. I only hope I haven't screwed up the fuse block with my multi meter probes...

 

[ZeroGravity58]

You did install the relay with the compressor correct? Finding a fuse won't screw anything up. If you are connecting a direct draw to a fuse and not using a relay then yes that can screw things up.

 

[2004LB7]

you also dont need to pull the fuse to check for power. there are little metal dots on the top of the fuse above the pins that you can probe with your meter. and you should have RAP power in the foot well

 

[gjk50003]

You did install the relay with the compressor correct? Finding a fuse won't screw anything up. If you are connecting a direct draw to a fuse and not using a relay then yes that can screw things up.

Airlift provided a short wire with a 15 amp fuse in it, said to connect one end to the power to the compressor and the other to a 15 amp or greater fuse. So that's what I did. Found a 15 amp fuse that was power on only when key was on, and used their spade connector thing to shove in with the fuse. The compressor worked with key on, but I got error messages galore, and when I turned the key to start the dash just went black and nothing happened!

 

[ZeroGravity58]

What Im getting at is did you use the relay? You should wiring the relay in and one wire goes to the battery with the fuse, One wire goes to ground from the relay, another wire is a trigger wire that goes to the fuse box, the other goes to the compressor. If you left out the relay and wired the power from the compressor directly to the fuse box then yes you will have problems. What you are saying sounds like you ran the power straight to the fuse box without the relay and are using a factory 15amp fuse for your power. What 15amp fuse did you use? Some of the 15amp key only fuses are ECM fuses

 

[gjk50003]

What Im getting at is did you use the relay? You should wiring the relay in and one wire goes to the battery with the fuse, One wire goes to ground from the relay, another wire is a trigger wire that goes to the fuse box, the other goes to the compressor. If you left out the relay and wired the power from the compressor directly to the fuse box then yes you will have problems. What you are saying sounds like you ran the power straight to the fuse box without the relay and are using a factory 15amp fuse for your power. What 15amp fuse did you use? Some of the 15amp key only fuses are ECM fuses

Yeah I don't know anything about a relay. What relay?

 

[ZeroGravity58]

Every airlift compressor I've mounted comes with all the wiring. It should have a little square box with a 4 wire harness attached to it. You need to wire in this harness with the relay. Hopefully you did not fry anything but a factory 15amp fuse is set for the load that is currently on it. You can't add another 15 amp circuit to it. Look up how to wire in a compressor

 

[ZeroGravity58]

Here is how you wire a relay

 

[TheBac]

Moved this into Electronics. Looks like you guys have a solution covered.

 

[gjk50003]

Every airlift compressor I've mounted comes with all the wiring. It should have a little square box with a 4 wire harness attached to it. You need to wire in this harness with the relay. Hopefully you did not fry anything but a factory 15amp fuse is set for the load that is currently on it. You can't add another 15 amp circuit to it. Look up how to wire in a compressor

So I pulled out the instructions that came with the compressor and yes, there's a relay pre wired into their harness. I used their harness and tried to connect exactly as instructed. I just don't think tapping of a fuse is a good way to do it on threes newer trucks.
How else do you power the compressor?

 

[gjk50003]

So looking at the drawing you posted, I could just come right off the battery?

 

[JoshH]

Did the truck ever start after you hooked up the compressor? I would start by undoing everything you did and make sure you didn't leave out any fuses. Check all the fuses you touched to make sure they have power on both sides and are fully inserted into the fuse block.

 

[gjk50003]

I undid everything i had done, checked that all the fuses were in the right spots. But I found that some of the fuse slots had been spread and the fuses were loose. This is beyond my level of comfort, I've never liked automotive electronics!
I had the truck towed to the shop yesterday. They called this morning and said the fuse block is not repairable...

 

[2004LB7]

it is repairable but many shops, especially dealerships, don't really repair anything. they are parts replacers. Since you are not comfortable with electrical, I say let them replace it and get it running again. when you get it back. put the +12 volt wire from that diagram above on the RAP power down by the foot well. if that line is not on switched power then it can run with the key off which can run the battery down

 

[ZeroGravity58]

Even if you used the relay you can't wire the hot side to the factory fuse box. You only use the fuse box for the trigger wire or RAP. I use the above RAP power for gauges when I install them in the truck. Let us know what they tell you.

 

[fajitatone]

Who makes a MOLEX for that connector? It'd be great to just wire into a connector and plug it in.

 

[gjk50003]

So it turns out that by probing the fuse block with my multi meter I spread some connectors beyond use, and they said pushed some down out of contact with the fuses. So replaced the fuse block for $400 and everything's great.
I will not mess with that again! I'm putting a switch on the dash for the compressor and running off a 12v connection with the supplied 20amp online fuse. It's working great.
Thanks for all the advice, obviously I had no business tampering with fuses. Things have changed so much that I'm out of touch with the newer vehicles!