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

At first I thought all the relays used would be in the bussman but for some things it seems remote relays might be better. One example I'm pondering is with a compressor and tank mounted in the right side bed rail. I'll have tank pressure air going to a guage in the center console next to the switch so if I place the pressure switch and relay there as well I can shorten all the wire runs and only main power goes back to the compressor. Instead of feet of wire between the switch, relay, and pressure switch there are only inches. For a compressor alone with no tank the situation would be different, there I would use one of the rtmr relays. The neat thing about the bussman is it has the flexibility for either approach.

 

I believe the Bussmann can only handle ~30 amps per accessory (I could be totally wrong and remembering completely in correctly) and since a compressor draws more than that, an external relay would be needed anyways. I have my compressor in the driver side cubby and put a relay back there like how you described. I do have a fused power lead from the Bussmann going to my switch so I can turn on the compressor anytime

 

My compressor uses a 30A fuse so whether the relay is in the bussman or not isn't an issue in this case. Anything with a higher draw would require the relay to be external but the point is that sometimes it can make sense to not only have the relay outside the bussman but to locate it either close to the accessory or close to the switch.

 

Great build!

I have two questions for @tacozord

1. I am bothered by rotating the relays. As long as the relays don't have internal back EMF diodes across their coils, you could still connect ground to the relay bus and have ground on 86 and supply power to pins 85 on the relays. By rotating the relays you miss out on being able to use dual 87 output relays. Anything else I am missing in the reasons for rotating them?

2. I looked through the thread and couldn't find it, could you post a circuit diagram of the entire setup please?

Thank you.

 

Wouldn't you just add another metri pack 280 connector to 87a?

 

I wondering if my understanding is sufficiently accurate. Below is copied from the info thread on motorizing the rear slider. I've read that there shouldn't be an issue with reversing polarity through the coil so that I could wire the 2- 5 pin relays as described below but with the relays installed upside down so pin 85 is grounded to one internal busbar as layed out in this threads op by tacozord. The switch would be the dpdt sienna switch and would have 12V in and the two out(s) go one each to the pins 86. Pins 87 would be jumpered to the external busbar. Pins 30 would be split so that each wire would connect to both motors. The purpose of this mod is to control two reversing slider motors(cab and shell) from one switch. I realize this could also be accomplished using a separate 8 pin relay but would prefer to add on other relays only after the Bussman is fully utilized.

Quoted from thread:
here is the diagram with the proper pinouts for the relays you need to use.

Do not switch wires on pins 87 and 30, you will cause an instant short to ground.

 

You're still able to use 5-pin relays even though I'm rotating them. I actually mention this in the tutorial. The top of the RTMR has a sticker on it. So you would simply need to remove a portion of the sticker for the fifth pin of the relay. Then connect a terminal and wire on the underside. No biggie!

This was posted in Part 4, Wiring, which shows just about every thing you need. After this, it simply becomes redundant with each switch and accessory.

 

Thanks, I ordered the 301-1C-C-R1 relays so next is choosing the actuators to use. I've got a ton of different mods to pull together and most depend on the rtmr for power. My del city order will be one of the last since that's when I have to decide on connectors. If the switch goes into the armrest next to the other window controls I'd use a 4-wire metripack, if I decide to put it in one of the 5 blank spots by the mirror controls I might use the 7-wire connector. Either one will let me use just one brand of terminals and pull both power and ground to the switch since I'd like it to be an always powered switch.

 

So after reading this tutorial 100 times both on TW and on your website, buying every tool and part, and assembling it over the last 6 months. I finally finished the install last night. Thank you for the very detailed write up.

 

Well done!

 

I'm not sure if this has been mentioned in this thread or not, but when I ordered the parts for this I copied the itemized list on part 2.

$20 12 Ga. Sealed Male Metri-Pack 280 Series Terminals #12048254 - (Pack of 25)

https://www.amazon.com/gp/aw/d/B00NVJ1N76/ref=ox_sc_act_image_1?smid=A6AY1HFZHO49U&psc=1


The above part is missing from the list but not from the more detailed explanation higher up on the page. Its the metripac 280 male terminal for connecting your accessories to the pigtails on the bushman.

Didn't figure that out until this thing was installed and went to make my connections.

I understand why a specific part # wasn't included on the itemized list. Due to terminal size being dependent on wire gauge which is determined by the accessory you are connecting. After having such a beautiful and comprehensive write up I figure its worth noting in there somewhere.

 

Also, the Bussman and the buss bars are both now 10-32 while the breaker is only 1/4" so you don't need lugs any larger than 1/4" unless at the battery terminals. A 10 pack of these is enough for all the cables including the battery terminals with two left over to redo oem main fuse box cable. If the battery terminals are 3/8" you can simply ream out a couple of them with a step drill.

 

That's some nice work. I'm still collecting stuff and adding things to plug into it.

 

Following this tutorial word for word. If anyone thinks they can get away with out buying the weather pack removal tool I submit to you exhibit A. Stuck the wire in a vice and tried pulling it out by the connector. It finally gave but so did my thumb.

 

It's not supposed to give at all. Not sure but I think tacozord mentions using a smallish flat blade screwdriver to release pins.

 

I had to pull it out because I got a bad crimp on the wire. Needed to pull it and redo. I tried undoing the pins with a couple small screwdrivers but no luck. The weather pack remover tool swallows the male connectors releasing the side pins. Just bad luck cutting my thumb when I yanked on it.

 

So it's some kind of narrow tube?

 

Awesome job! You must be happy.

 

Sorry about that. I did mention earlier in Part 2 where I originally listed the Metri-Pack male terminals that various sizes will be needed:


When making your parts purchase, you may want to buy terminals for other gauge sizes. These would be used in the Metri-Pack connectors for your accessories. Suggested parts to purchase would be:

• Metri-Pack 280 Sealed Tanged Female 14-12 AWG – 12129493: Waytek Wire
• Metri-Pack 280 Sealed Tanged Female 18-16 AWG – 12077411: Waytek Wire
• Metri-Pack 280 Sealed Tanged Male 12-10 AWG – 12048254: Waytek Wire
• Metri-Pack 280 Sealed Tanged Male 14-12 AWG – 12129497: Waytek Wire
• Metri-Pack 280 Sealed Tanged Male 18-16 AWG – 12048159: Waytek Wire

Anyway, I tried to update the tutorial to included this information in the list at the bottom that you copied, but when saving the post, I got an error that I was over the 60000 character limit. Go figure!

 

Sounds like you're being resourceful. That'll work!