DIY - Build and install a Bussmann RTMR Fuse/Relay Block

Are you talking about the 5 fuse only circuits or the 5 relays? You don’t have to go 5 x 5, you could do all 10 fuses as fuse only(better served using a fuse only panel such as blue seas) or link the 5 fuse only circuits to external relays or anything in between. I bought my truck used and it came with a cap installed having a fused wire off the battery. That got moved to one of the fuse only circuits. I added extra horns and fogs and those use 2 of the relays (horn relay triggered by the oem wire). 2 other relays are jumpered to be motor reversing for cap window control. I also added a separate 6-way fuse panel in the cab (1/2 ignition hot, 1/2 always hot) for interior stuff like heated seats, heated mirrors, power ports,
Sky’s the limit really, just think about what you want and where and when you want to use it and go from there. The RTMR is great for making a portable power center in the back as well. You can power it from the truck or from solar/house battery or both.

Most of these panels seem to be limited to 30A per circuit with different max current levels so compressors are a no go.

 

I'm working on my RFRM right now because I engineer one way: over. So I have loads of fused circuits. I doubt I'll find uses for the 20 I have left after using fueses for the 10 relays, but wanted to know what I could do with them and still have control (e.g. a switch). I guess if the switch is rated for the current, then it shouldn't really matter, right? So long as it's within the RFRM limits, of course.

Is your electrical work in your build thread (if you have one)?

 

Just parts that are unique like the switch panels and fuse panel under the center console. Tacozord has the best, most complete thread on how-to and this one is where I look for ideas and to help others with theirs. Not an expert by any means but an extra set of eyes can spot errors or give pointers. Many accessories are fine for direct switching but the switch style I favor(long & short tacoma push switches) are limited to 3A max so I just use relays for all switched accessories, plus they’re easy to mod the color/brightness for consistency. It also keeps high current wires out of the dash and sometimes shortens those runs.it also allows you to daisy chain all but the relay trigger wires so you have one fused power wire supplying all of the switches in a bank instead of heavy gauge fused wires for each switch. Vastly more simple to manage and keep track of.

 

I looked at the rfmr but although it fits the location the wiring under it get too dense for me so I’m using sub panels for distribution in the cab and bed. I acquired a set of the small bed cubbies and have fitted a second rtmr in one (for solar/camping) but haven’t installed it yet.

 

Honestly - it depends *entirely* on the build you want to accomplish. The Bussman RTMR is a custom build switching unit. It can be all fuse, OR it can be all relay. YOU decide on what it will be.

As far as examples, here are a few:

• High power LED lights (20-30a)
• Ditch lights
• Rear Lights
• Front grill lights
• Compressors
• Winch
• Heated Seats
• Stereo Amp
• Dual USB sockets (Fear)
• Dual USB sockets (Front)
• LED Cup lights (any color)
• Hood Light
• Front Camera power
• Waterproof USB socket (truck bed)

Obviously just about anything that comes to mind - you can put on a Bussman RTMR. I have two on my truck, both are dual fuse and 30A relays.

 

These are good ideas. Hood lights I wanna do, and I have some cheap rock lights from Amazon that should be low current enough for typical switches. Heated seats would be good if the switch supports the current (have done no research into them). I did make a better USB charger for the cab that I could move over as well. It currently uses an add-a-fuse. I'll add bed stuff down the road.

 

Not supposed to run a compressor or winch through a Bussman or Blue Seas, both are limited to 30A per circuit. Anything over that needs a dedicated fuse/relay sufficient to the task. Some compressors maybe but certainly not an ARB twin which draws more than twice that as it approaches full pressure.

 

I could use an extra set of eyes on my setup as it currently stands. The RFRM does have an internal busbar but not one that overlaps with any of the relay pins. So I figured I'd just make jumper wires to get to the other side of the fuse plugs then use a fuse to reach the internal busbar. Same concept as with the power.

Right now, I've got two 6-way connectors, each with 5 relay circuits and a ground. I've made 10 accessory connections (not shown) for the relay and the fuse side of the house. I'll plug the rest of the cavities.

On the mounting panel, bottom side, I have the two external busbars. I'm hoping there's enough space to get all of the terminal rings in place without too much tangling. The spacing of the busbars allows me to use a single pair of screws to mount the busbars on the bottom and a 100A circuit breaker on the top. I test fit it all in the truck and it looks good, granted there's still more wires to put in place.

Aside from the modifications I had to do for mounting and using an RFRM, I'll be following the rest of the guide as is. Have I made any mistakes in wire routing? Or anything else.

 

<edit>. Oops, missed that you’re using a different relay box.


Your wiring purpose may be different than mine, so the connections may be different. Attached is mine below, which appears different than yours. Granted, it’s been in limbo for a little while so I haven’t confirmed mine works as intended.

 

If you’re going to tap the dash light dimmer circuit for the switch leds(both switched and unswitched) the extra ground wires(sixth wires with ring connectors) aren’t necessary and you can use those as trigger wires for separate higher current relays that need to supply more than 30A such as for a compressor. Those need a separate fuse source also since the 30A limit applies to the fuse only circuits as well as the relay circuits.

 

I like the way you think.

 

Exceptional instructions, @tacozord. I learned a ton.

 

I think it's ready for installation. I tested all the relays and heard satisfying clicks and hooked up my cheap rock lights and turned em on with my power supply. Everything appears to be working. I will be installing SDHQ terminals which will be the attachment points for this unit.

My wiring is pretty messy given space constraints. I will probably remove a few of the unused fuse accessory leads. Does anyone see anything I've missed with the way I've routed everything?

 

If the ground busses interfere with opening the oem fuse box you could mount them parallel to the Bussman with a side extension plate. Routing looks exceptional, just need to attach the switch ground somewhere.

 

Yes, you are correct - the

$600 CKMTA12 '12V' On-Board Twin High Performance Air Compressor, Ideal for Air Lockers Locking Differentials, Tire Inflator, Air Horn, Air Tools and Pneumatic Tools.

CKMTA12 has a current draw of 28.4a to 50.4a through the *relays*, but the *switches* are 12v. I built a second Bussman for the oddball wiring for both the Winch and the ARB Compressor switches. I liked how it looked and it allows me to be creative with wiring instead of having a jumbled mess under the hood. I just like it mostly because its waterproof and everything runs through the box.

As for the winch - it depends on the make and model you would buy - and whether it has a winch controller that is wired or wireless. If Wireless - you buy the controller and wire it up. Done. Mine is wireless. I have a switch that turns on the wireless winch receiver. Thats all it does. I don't want my wireless controller to turn ON when the car turns on. I want to control that with a button. Hence why I wired it through my bussman.

 

Yeah, ARB has built in relays but some others don’t. In any case the power for any of them should be routed through something that can handle the current. For the switch alone it’s not an issue but the power fuse is since the mini fuses used in a Bussman only go up to 30A. A different fuse type and holder are therefore required. ATO goes to 40A, others like ANL go higher or just use an appropriate breaker.

 

I considered side plates from the get-go but went for the quicker (lazier) solution. I am partially regretting it. I feel like I'm going to revisit the wiring one day. I should be able to get a switch ground with the daisy chain harnesses I have.

Thanks for the help and compliments!

 

It’s a treat for me to see what others do.

 

Well here's something else to see. Not enough space:


I knew it'd be tight (so to speak) going into this but was hoping I could work some magic. I could probably get things juuust right to have enough space but then reaching the accessory plugs would be near impossible for some of them.

As of right now, I see two options: remove some of the accessory cables, particularly the fused ones, to free space and hope I can still reach what's left. I got the RFRM because I wanted more relay spots so I'd like to keep all 10 there if I can.

Or...make new wiring for all the accessory leads and route them to just behind the headlight, between the battery. There's loads of space there. But that means more work, more wire, and a further distance to route accessories.

I don't think I can swap this setup over to the passenger side without finding anotherounting tray since it pokes forward into the engine air filter box.

Despite all this, it is pretty satisfying hefting this component around. Very compact, all things considered.