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

Subd

 

If the switch only activates a relay then the load is only~100mA per switch plus the leds which are 10-50mA depending on what resistors are used in the switches so there's no problem ganging several switches off of one add-a-fuse(3A fuse is enough). As far as led power there are a few ways to go, you can have the base indicator on all the time(regardless of dash lights) by jumpering switch power to led power(switch on illuminates the other led). Have it come on with the dash lights but not dim by tapping dash ligh power but not use dimmer ground just chassis ground. Or use both dash power and ground to have them come on with the headlights and dim with the dash lights. Since you have a '15 dash light power and dimmer ground are most easily accessed via the plugs on the back of the AC controls (green and green/white) it's no more difficult than tapping any other source for power/ground so why not?

The 5 pins are misleading as the center pin isn't used, it's not connected to any copper traces on the switch pcb inside the housing. Switch on led power is already routed on the switch pcb and doesn't come from any outside source. This is why even though there are 5 pins there are only 4 wires in the plug.

 

Perfect, this is what I was after.

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As far as led power there are a few ways to go, you can have the base indicator on all the time(regardless of dash lights) by jumpering switch power to led power(switch on illuminates the other led).
[/QUOTE]

This is what I was trying to describe. Again perfect!

[/QUOTE]
Since you have a '15 dash light power and dimmer ground are most easily accessed via the plugs on the back of the AC controls (green and green/white) it's no more difficult than tapping any other source for power/ground so why not?
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Either way I will use an add a fuse to tap a power that's hot only when ignition is on, so why also tap into the ac when it would be easier to just jumper. That was my thinking.

Or are you saying I can get ALL power and Ground from the dash light power and skip the add a fuse?

 

TW learning curve. my apologies. Note to self use multi quote and don't copy and paste quote

 

Yes this was helpful. I think I finally understand why people are pulling power from two sources. One to power the switch(add a fuse) and second by tapping into the dash lights so your LEDS are not on during the day when your headlights are off (like all your other dash lights). Plus the added benefit of optional dimming.

My add a fuse will be only hot with ignition by the way.

 

As far as led power there are a few ways to go, you can have the base indicator on all the time(regardless of dash lights) by jumpering switch power to led power(switch on illuminates the other led).
[/QUOTE]

This is what I was trying to describe. Again perfect!

[/QUOTE]
Since you have a '15 dash light power and dimmer ground are most easily accessed via the plugs on the back of the AC controls (green and green/white) it's no more difficult than tapping any other source for power/ground so why not?
[/QUOTE]

Either way I will use an add a fuse to tap a power that's hot only when ignition is on, so why also tap into the ac when it would be easier to just jumper. That was my thinking.

Or are you saying I can get ALL power and Ground from the dash light power and skip the add a fuse?[/QUOTE]
It might be possible to do that but then the switches would only work with the headlights on so no, I'd use an add-a-fuse or fuse tap for switch power but the only thing you need ground for is the leds so why not use dimmer gound? Not sure what the difficulty difference is between a wire jumper and a wire to a tap but it seems minimal(not zero but certainly not extreme). I'll admit to a greater than average level of OCD so I can understand that others might not take things as far. I went as far as changing the resistors in each of the switches to bring the illumination levels closer to the rest of the dash lights.

 

Okay, you got me thinking now. Screw it I'll just tap them both. I was looking for the easy route.

switching resistors in the switches? Ha you are the man. I'm just starting to read about resistors and learn about them. I plan on adding aftermarket reverse light pods to my bruteforcefab rear bumper (being built)once I get it. I want them to automatically come on in reverse, but also be powered by a switch (in the panel I'm working on now). I know I'm going to throw a resistor in there, so been reading up on it.

as always, thank you @bagleboy

 

my easy route was going to be to jumper all positives together to the add a fuse and jumper all the negatives together. I was going to run the negative wire out to my blue sea negative bus along with the individual wires from each switch to the relays (underside of my aux fuse panel).

 

Use a relay that is triggered by either the reverse lights or the switch with a diode on the reverse light wire to keep the stock lights from coming on with the switch. The diode makes the wire a one way conductor. You can put the relay in the driver's side rear light bay and run the switch leg and relay power along that side frame rail. Then run your pod power from the relay and either ground to the frame or use a 3rd wire back to the engine bay. I dont think you need resistors for 12v lights. The switch leds need them because those are 3V devices. If you can find the reverse wire in the dash(no idea on that)you can put the relay up front and just have power/ground back to the lights. I just switched to led bulbs for my reverse lights and found that to be more than enough but I don't believe the new bulbs are sufficiently robust for continuous use as pods would be so you're probably smart to add those. The filament bulbs used for reverse/brake/dome/etc. aren't up to more than very short periods of use, leave them on and they die young.

 

The buss ground is to pick up the ground returns of all the lights plus any other grounds you want secured better than to the frame(ground faults are notorious in auto applications so for me this means everything) using dimmer ground will delete one wire through the fire wall. If you're using the overhead location for switches like the op there's a ton of space above the instrument cluster that reaches from the A-pillar to the radio and represents a much cleaner access channel to dash center for wires or extra camera feeds or if you plan to locate switches below the AC controls like I did. Saves lying upside down trying to get around the pedals and zip ties galore.

 

Mother of god, this write up is so cleeeaaaannnn. Thanks @nazlax10

 

The original post to this thread is awesome! .....and...overwhelming....

I have a question that is actually relatively simple. Perhaps the answer is in there, but I didn't find it at first parse. Asking in case someone knows off the top of their head:

Q: Where is the best place to tie into accessory power in the cab (or out of the cab I guess) for use in powering all items that you only want powered when accessories are on?
Basically I'm going to install two Blue Sea Fuseblocks. I know how I'm going to run and attach the one under the hood...it is easy because it is on the other side of all the relays. I just hook it directly up to the battery. But the other one I want to put in the cab to wire up all the switches that I've put in (or may put in) that need accessory power (for light bar or compressor or whatever). So I'd like a nice fat wire or connection that I can tap to power the fuseblock I'm going to use to break out power to all these switches so they only work when accessories are on. Where is the best place to tap in? Currently using add-a-fuse to do power stuff and I want to move away from doing that.

Truck is a gen 3.

 

You can run an entire bank of switches off of 1 add-a-fuse if the power for the accessories is controlled by relays. The relays can get power directly from the battery but will only function with ignition on because the switches are only powered with ignition on. If the accessories are inside the cab then it makes sense to put the fuse block for those in the cab along with their relays but if the accessories are outside the cab(lights, etc.) then the best way is to have the fuses and relays close to the power source(battery) and only have the switches in the cab with one multi-wire cable going out to the relays.

 

For those that are having trouble finding a tray for the Manual, check out what I did:
- bought a stock tray for the 3RD gen auto from Powertrays.
- on the clutch reservoir, I cut the straight part of the hose that goes from the reservoir to the firewall down by 5” and moved the reservoir back towards the firewall.
- there’s a large bundle of wires mounted to the fender wall, I removed that grey plastic wire holder and reamed out the hole it was in (it was a rectangular hole) and then inserted an 8mm rivnut in there, then installed a second one and was able to use the stock reservoir mount, keeping a stock look. However, you’ll notice the stock holes are angled, probably to compensate for the built in factory Taco lean , repositioned reservoir is a bit off, but you’ll never notice.
- powertrays mounted up with plenty of room to get the stock fuse box lid out.


Viola!!!

 

I bought the bussmann tray for the 3rd gen TRD-OR auto

 

I dig it, awesome work! Wondering if that’ll work for my S-Stech system which takes up a lot of real estate.

 

Wow! What a write-up!

 

Nice

 

Damn! Definitely going to be doing this in the summer. Thanks!

 

Apologies if this has been asked, but I see a 100A circuit breaker in the product discussion area below. The RFMR is rated at 80A, and I've read a circuit breaker should have an amperage slightly greater than the device is protects. That said, is 100A too much greater? If the current rises to 90A, the breaker wouldn't pop but the RFMR and associated wiring could sustain lasting damage.