OEM crimped connectors for relay and fuse box

I looked for an existing thread on this, but didn't find one. I apologize if I missed one. I do see a similar thread on the Tacoma forum.

I would like to install the ARB dual-pump air compressor and a reservoir in my new (under warranty) 2024 Tundra. Looking at the RH engine compartment fuse and relay box, there appears to be a lot of space for additional relays in the box (since I went cheap on options!). I believe there is enough physical space for the compressor directly above this relay box if I fabricate a hinged mount for the compressor. The compressor requires two 40A relays and fuses. I would like to hear from the forum on the following questions (and any other advice offered):

1: If I can source (more on this below) the loose, OEM crimp terminals and then wire the compressor directly to the fuse and relay box, using a suitable OEM relay, will it likely void my warranty?

2: Aside from voiding the warranty, is there a reason not to wire the compressor to the OEM fuse and relay box? Assume I will use proper crimpers, wire gauge, and good shop practices, and I have sufficient experience.

3: If the minimum quantity of crimp terminals is large, would anyone be interested in going in on an order?

I started down this rabbit hole, looking at the seemingly-sufficient available space above the RH fuse and relay box, and thought, "That would be a nice, short wire run!" Then, looking in there, I found two spots that would accommodate an OEM 50A relay, and 50A fuses (I will use 40A components, which have the same form factor). One is populated with terminals, and is labeled AIRSUS (for the auto leveling suspension option I don't have). The other is a hole, into which snaps a plastic relay block (I'm trying to identify this part number, but I expect I'll be able to do it). Rather than dissect my new truck, I harvested a fuse and relay box from a 2007 Toyota Sienna at the pick-n-pull for $25 (it came with a nice inventory of used relays as a bonus).

The terminals in the relay blocks and fuse sockets in the donor fuse box are apparently identical to those in my 2024 Tundra. I de-pinned a 40A relay block and a fuse socket to get the terminals on the bench, I photographed and measured the terminals, and then I had a long email exchange with a company that builds and repairs harnesses (they were very patient with me). They identified the three special terminals, and can sell them to me in a minimum quantity of 20 pieces each, to the tune of ~$400.

If I can't afford to source the loose terminals, I do have some nice 10ga pigtails from the donor box that I could use with crimped "environmental" butt splices (the kind where the sleeve and the heat shrink are separate, and create a water-tight connection). So I could cobble the wiring together that way, but Questions 1 and 2 above remain...

The mystery on identifying these terminals seems to be due to the fact that Toyota and other auto manufacturers list a part number for the entire harness, not the terminals. The person at the parts counter at the dealership definitely can't help. I believe connector shells are easier, but the identities of the terminals themselves (especially in the fuse and relay box) are apparently proprietary information. I spent hours on various sites trying to match them visually with similar terminals offered, but just wound up frustrated and behind on work I should be doing. I know there are many nice options for adding additional busses via the battery post, etc. but I thought if I could pull this off it would be extra nice.

Thanks for any and all advice!

 

I am currently working on a similar project, also a compressor, but only one and only 25 amps. I am looking on DigiKey for the terminals right now, but I did buy a fuse box from a scrap rig off of ebay. My plan was initially to disect that and see what I can do with it, but I'm not a fan of having to solder stuff that will be in the engine bay for who knows how long.

As far as the warranty goes, denying a warranty claim does not mean voiding the warranty. Toyota may refuse to cover certain repairs under the warranty, and when they do deny warranty claims, I think they have to provide a reason. If their reason is that modifications were made, I think that they have to prove the modifications caused the issue. Don't quote me on that though. That is what I was told in regards to the manufacturer warranty, but I don't want to give you bad info. I will updatd with info on the fuse and relays as soon as I have some.

In your case specifically, 80 amps is quite alot, even for a compressor. I would excersise caution, I know for a fact that alternators start having issues much sooner when they are under a more significant load. A 120 amp alternator should not be subject to any more than 90 amps for more than a few seconds other than at startup. Not sure what the alternator on your rig is rated for, I know mine ('21) is only 150 amps.

 

If there was enough room above that relay box, the aftermarket would've already done it.

 

There is ample room for accessory circuits.



The reason people don't usually do it this way is because it's a PITA. The bottom of the box is a mess, and everything is taped up. The spare box I bought might be worse because it was cut off of another rig.



The bigger issue is finding the right crimp on terminals for the relays and fuses.


I am still looking for these, they are single use, so after they've been crimped once, they are pretty much garbage. I'm planning to contact the dealer on Monday, they should have something. I guess mice getting into the wiring is a prety common thing. The only other option is to solder and shrink wrap the wires from the scrap fusebox to wherever they need to go. Not exactly ideal, but still far better than mounting a relay in an impossible to find spot with a self tapper.

 

The issue isn't the wiring, it's the size of the ARB Dual Compressor.

 

No, its the damn terminals. There is plenty of room for the compressor in a bunch of different places. Mounting is usually the easy part if you have a little practice with fabricatiing brackets. Wiring is not so easy, even for me with a pretty good amount of practice.

 

What is the deal with the company that is offering to sell you the terminals. Do they have a whole bunch of them? I might be willing to split an order with you if I can for sure get all the terminals I need.