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

Finally got min finished up this weekend! Only thing connected currently is my carling style USB charger on my iggy switch panel. Now comes my headlight retrofit project, as well as bed and hood light install! Thanks again @tacozord!

 

Thinking of building this. I haven't priced it all out. I know some of the connectors/plugs have a minimum order. Anyone that has made the minimum order have extra to sell? Is it worth it, or is the minimum order a negligible amount more?

 

You can use the extra terminals for making connectors for all your lights and other electronics, but you'll then need to order the Metri-Pack 280 male and female housings and retaining clips as well.

 

Awesome write up! Got mine done in a couple of days and installed in a couple of hours. No more tapping into corner lights. Also built three extra Bussmann blocks; they are for sale in the "1st and 2nd gen for sale" pages. Thanks for the write up!

 

I'm wondering if you can leave out one or more of the relays and wire those circuits up for fuse only so that you can have more than 5 fuse only circuits. Now that I have my system planned out I don't think I will need relays for some of the lights since the LEDs draw such little power.

 

Instead of bridging the fuse to the relay, couldn't you just make more fuse only leads and plug the relay side with the cavity plugs? So instead of having F1R1 F2 F3R2 F4 ect. leads, you would just have like F1 F2 F3 F4 F5R1(or 3 if you want to keep it the same as in OP).

 

Yeah. I think that's what I was thinking.

I'm also trying to remember if you can plug a mini fuse where the relay was. That way removing one relay might free up 2 fuses.

 

I'm not sure what accessories you're using and how much power they're drawing, but just a heads up about LED current levels and safety. A typical LED draws about 20mA at 12v. So if you have ten LEDs in a foot of light rope, then that's 200mA per foot of lights and no longer considered low power. If you want this circuit switched, then I'd definitely use a relay and not control directly.

Here's a link about electrical safety and the dangers of different current levels:

https://www.physics.ohio-state.edu/~p616/safety/fatal_current.html

 

oic.

I think I have about 48W in the rear backups and prolly about the same in fogs and bunny burners each. I was thinking 4 or 5 amps would be pretty typical for an OEM fuse only circuit.

 

You definitely want a relay on those!!!

 

Get these in the mail yesterday from a forum member as thanks for the tutorial. So very grateful. Thank you Taylor!

 

I've got everything I need except the 10 AWG TXL Red & Black Wire, I've been searching locally to see if anybody carries or can get it for me. I've taught about 9 different automotive electrical shops about why it's such a special wire and what it's used for, but cannot find it for the life of me.

I didn't purchase it from Waytek because they want 68$USD for a 250' spool, when I'll never use that much. If only someone would send me like 10' of each! (hint hint) If not I'll have to just buy it when I return from Moncton, NB.

I'm aware I can use different wire, but I'd much rather use TXL for the specific reason of it fitting in the cavity plugs without being too tight or loose.

 

I just got the 12ga GXL from Waytek. I think it was about 40 something for the 250 spool. It fits the RTMR seals better and has plenty of ampacity for my circuits.

 

@Tsumara

 

Ok, so this was my solution to get a pair of lights wired in parallel. Basically the same as I show in the diagram except I put the double wires on the female side so that the wiring harness could be removed.

Anyway you can just fit both a 12ga wire and an 18ga wire into the 12ga seals and squeeze everything together in a 12/10ga terminal. Not really ideal since it's not a perfect seal with two wires.

 

Sub'd so I can find this easier. Also want to say thanks! This is incredible!

 

Awesome write-up. I'd like to add a recommendation for tools. I'm an electronics enthusiast and agree with the soldering station, but having a quality soldering pen is a lot easier when working outside on the truck itself, rather than lugging around your station. I'd recommend a

$34 Hakko FX-901 - Cordless Soldering Iron

Hakko FX-901 pen and for the station a Hakko FX-888D. I built 90% of my Bussmann RFRM inside and on a soldering station, but those quick fixes outside the soldering pen is a lifesaver. A good set of

$42 QuadHands Classic Workbench Soldering Helping Third Hand Tool | 4 Gooseneck Flexible Positionable Arms | Sturdy Base | Rotating Stainless Steel Alligator Locking Clamps | Circuit Board Holder | USA

helping hands also can make things much less frustrating.

 

Does that 888D get hot? I've been through several soldering irons and heat guns and mini torches and nothing seems to work right. It's like solder doesn't want to melt in my part of the universe.

 

Very. Hakko's are very well known and used in the electronics industry. Make sure you have good solder.

 

@yotastaco what solder do you use?
TIA