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

you get the mount yet ? how it work out

 

"So I started wiring up my Bussmann this weekend and followed the write up where applicable. I bought my Bussmann used and pre assembled but I figure it’s a similar idea. I have model: 15303-5, so I have the fuse side bus bar but not the relay. I dont need to flip my relays and the individual before me ran all of the grounds into a higher gauge wire and grouped them together. I’m not opposed to this, but if I’m not mistaken, I still need to figure out a ground for theaccesory itself yes?

I was even thinking about running an external ground bar like the one in the thread just for the accesory grounds. What do you guys think? Is there a way I can integrate the accesory ground into the fuse block?"
Yes, power runs from the relay to the accessory and is either grounded there at the chassis or returns to a buss bar that is cabled to B-. The ground connection for each relay is low current as it only carries the switch current to activate the relay and not the device current.

You can ground the devices with a common buss bar located next to the Bussman like in tacozord's excellent thread.

 

How many amps should I fuse from the battery headed to the box if I plan on using all the circuits for the cooper bussmann?

 

The cooper bussman we are using is rated at 80A so that's the rating of the fuse or breaker you put between it and the battery.

 

If you plan on exceeding 80A you will need another fuse/relay box or different brand like seagate rated at 100A and if you're going to exceed that you will probably need a higher output alternator and a dual battery setup as well.

 

Have not gotten it in the mail yet. Still waiting.

 

No. IMO rubber between a plate and the fender will likely increase vibration of the plate. Bouncing and vibration of fuses and electrical components isn't good for them. Also since you will have wires running off the plate to various accessories and to your battery, more movement may cause wear in the wires where they touch each other or engine parts. This rubbing may lead to a short.

 

Just a heads up regarding the op's set up. The relays are grounded to one of the internal buss bars with a 10awg jumper to the external buss bars and B- cable but that ground is only for the switch signal current, the accessories are all grounded to the external buss bars. My set up will have two of the five relays as 5-pin to operate dual sliders for the cab and cap.

-edit, this part is wrong- In this arrangement the internal ground buss and hence the 10Awg jumper carries the accessory ground current as well as the signal ground-
The internal buss still in only carries the signal ground, the device ground must be jumpered over to the buss bar.

 

This is a sweet detailed write up but damn.........i'd just pay someone to make me one.

 

Alright, so I am working on my fuse block and following the write up with a few alterations to fit my desires. I want to run this by the peeps on the thread to confirm that my wiring is good before I start plugging in power.

I am doing the overhead switch panel in the sunglass holder and I have already made the wiring harness with my alterations. The primary reason I have to modify from the write up is that I am integrating my ABS delete into the switch panel. I wanted to do something more unique and uniform than a toggle switch hidden somewhere under the dash.

I contacted OTRATTW when ordering my switches and was told that I need a different switch layout than what the OP used in the write up that would allow me to illuminate both LEDs while keeping a complete circuit and then interrupt the ABS circuit when the switch is engaged. (Obviously) He sent me V4D2 which is a switch that has the LEDs independently wired from the switch operation. I am going to be integrating this into the panel with the rest of my switches that power my accessories.

With that said, my wiring is different from the first and second switch, and I want to get a second or third set of eyes before I plug in power. Basically, using the same terminals within the writup I used the wiring diagram below for the LED independent switch. Let me know how you would wire everything up.

So far, with the independent LED switch listed first, I have terminal #10 going to terminal #6; terminal #8 going to terminal #2; terminal #9 going to #7; and terminal #7 going to #8. From here, I was going to run the positive side of the ABS system to terminal #2 and then run the negative side to #1 or #3. I think that just alters wheatger the circuit is completed with the switch on/off.

Thoughts? I know it’s a rough description, but I can ty to clarify upon request.

 

Seems like you could do the same thing with a regular switch and 5-pin relay using the normally closed relay position as the abs on/led off position and flipping the switch to on lights the LED and turns off the abs.

 

That was discussed when planning the job but this appears to be the slightly more straight forward route. I had to buy a switch either way. I don’t fully understand the relay route and that would require me adding a relay somewhere within the circuit.

 

This doesn't make any sense. There is no terminal 6 and connecting 8 to 7 is just going to short power to ground.

 

I think there is a little confusion here so I’ll try and elaborate. Im running, in series, the switch with the schematic above to the switch with the schematic below. Two different layouts and I have listed the terminals that I have jumped to respectively. I hope that clarifies?

 

A relay is just an electronically controlled switch and the 5-pin version allows you to do more. Unactivated, the relay is open on one terminal and closed on the other and when activated they reverse, the open terminal,closes and the closed terminal opens. You would use the normally closed terminal(87A) as opposed to the normally open terminal(87), both of which make their connection to pin 30. You're existing switch would turn on the LED indicator at the same time as it tells the relay to turn off the abs. The switch would have the same led connections as all the other switches in the panel and control a 12V signal. The relay would be installed where you want to interrupt the abs wire. The switch +/- wires go to pins 85 and 86(un polarized, so either way works) and the ends of the cut abs wire go to pins 87A and 30(again, un polarized). Done.
I realize this isn't what you need but maybe it will help you or someone else with another install. Or maybe I'm still totally confused. I've found there are some cases where it seems to make sense to have a relay mounted someplace other than in a common box, this might be one of them.

 

As far as you're switch diagram goes it looks correct to me. The lower led is on when dash lights are on and the upper turns on when the switch is closed. How the switch does this and interrupts the abs signal isn't so clear. Maybe it's a double pole switch with normally closed connected to abs and normally open to upper led?

 

Thanks is for the input and explanation. That does make sense but I’d have to play with it to fully comprehend the diagram.

A double pole switch sounds familiar from when I purchased the switch. From my understanding, the LEDs are independent from the switch operation allowing you to interrupt the circuit and not disrupt the LED operation. That is my assumption being this switch has an upper LED positive where the others use the power source on terminal #2 to power the LED.

 

It takes me while to wrap my head around any of this stuff so it's a treat when I can know it well enough to explain it.

 

I had the same issue as you. I thought about flipping the plate upside down but I fussed over bolting it on for about an hour or so. Finally, I cut a notch in one of the long holes and tightened the bolt with enough thread showing to slide the mount onto it.

I wish I knew how he did this. Would’ve helped since I scarred up my hands and was losing my mind.

 

I think he probably dropped the front end and motor out and did it from the bottom.