GMRS radio wiring question

[drowzyGX]

Hey Y’all,

My Midland MXT275 arrived today, and I’m trying to figure out the best way to wire it.

The plug it comes with is for the cigarette lighter and has an in-line fuse.

I don’t want to use the GX’s cigarette lighter. It’s already used for my phone’s mount (powered mount that auto-locks onto the phone and provides wireless charging).

I’d like to mount the radio in the glovebox, and have the wiring from the radio to the handheld unit figured out. Where I’m struggling is getting power to the radio. I’d like to have the radio always-on so it can be used when the car is off.

My tentative plan is to install an always-on 12v cigarette lighter port in the glovebox. That way I can simply unplug the radio from the lighter outlet when not in use, and not worry about draining the battery (but retain the ability to plug back in and use while the car is off).

Question 1: Is there a better way to provide always-on power to the unit while not having to worry about draining the battery? I worry that wiring directly to the battery would risk draining the battery.

Question 2: I already have HID lights with power cables wired directly to the battery terminal. For the always-on cigarette lighter, that would also need to run directly to the battery. This seems amateur and sloppy to have so many cables directly to the battery. Is there where an accessory fuse box like something from blue sea comes into play? Is it as simple as wiring that fuse box to the battery, then HID and always-on cigarette lighter to the fuse box?

Question 3: is there a better approach than the above? Should I just leverage the existing fuse box?

Appreciate any feedback here. Electrical is not my forte, but I want to do this once the right way.

 

[CO_Hunter]

Bluesea would be a clean and inexpensive way to go. Many ways to accomplish your goals. I have some pics of my under the hood, blue sea /solar/dual battery here in my build thread, post 102

Builds - CO_Hunter’s GX470 build

It’s a mix, some 1/8 and some just shy of 3/16.

forum.ih8mud.com

 

[drowzyGX]

Thank you for sharing that! Very interested in installing a blue sea unit, and will review the thread as I plan the blue sea install.

The more I read about the radio install, the more I’m finding suggestions to wire it directly to the battery for best performance.

I think I’ll wire it directly to the battery, with an in-line fuse as close to the battery as possible. Will use the blue sea unit to handle HID lights, incoming ditch lights, winch, and solar.

 

[jdevtac]

I agree with running GMRS straight to battery. Usually mitigates noise issues and such. Most of my radio installs I cut the original connectors off of and run my own harness to the battery. Usually they don’t leave you enough wire to make it to the battery. I guess manufacturers think the only place to install the radio is dead center of the dash.

Blue sea units are great but if you intend to add multiple relayed accessories, getting a unit with relays packaged with it will be a lot cleaner than mounting a relays somewhere in the engine bay in addition to the blue sea panel. If it’s just a few relayed items then not that big a deal. Other units accomplish the clean packaging but get stupid expensive for what they are. I run a diy Bussman RTMR build and it has worked well for me.

 

[NudeLobster]

I have my MTX275 mounted in my glove box (along with my Icom 2730A HAM) and have both powered off an ignition-switched add-a-fuse taps in the dashboard fuse box. I simply cut the cig adapter off, cut the wire to length, and crimp on the add-a-fuse. I cut off the crimps included with the taps and use my own waterproof insulated shrink wrap butt crimps.
Amazon product ASIN B08QJHXRN6


I used an RJ45 extension to a UHF radio jack toyota switch so I only have to open the glove box to retrieve the hand mic from storage and plug it into the switch jack. I bought my switch jack from Australia because I couldn't find a green backlit model available in the states and I wanted it to match the rest of the green interior backlighting.

UHF RJ45 Dash Pass Through with LED - suit Toyota Large

Description Select the LED Colour above in the drop down menu UHF RJ45 Dash Pass Through - suit Toyota Large with LED OEM Replacement Unit has LED which is illuminated when powered Simple and firm mounting for quick installation that will not rattle while driving Includes: 1 x UHF RJ45 Dash...

www.switchboss.com.au

 

[drowzyGX]

Oh man, you just triggered my OCD and now I may have to order that rj45 backlit switch. Didn’t even realize that was an option.

Thanks a ton for the details and pictures. That’s really helpful.

Definitely installing in the glovebox. I converted my CD player to a secret compartment. So I’m gonna mount it in there.

I really want to be able to use the radio while the car is off. So I’m gonna wire direct to battery, but the info you shared is super helpful. Really appreciate it!

 

[MintyGX]

This RJ45 connection is way cheaper and you can install it anywhere it fits. Will require drilling, but you save a switch opening.

https://amzn.to/3wVWUni

Here is my install on my Tacoma with the Midland MXT275, remote connection to the RJ45 and the magnetic mic install. I plan on running a similar set on the GX. The video may give you some ideas.

 

[drowzyGX]

Yo, great install video. Watched it while having my coffee. Appreciate the sentiment of turning a plug and play install into a multi-day project to have everything exactly how you want it.

Funny enough I got the same RJ45 connector on Amazon. I really dig the green backlit one, though, because it matched the oem GX switches so well.

 

[drowzyGX]

@jdevtac I read this incredibly detailed tutorial for a DIY Bussman RTMR setup. It was pretty overwhelming - tons of parts to order and what looks like 5+ hours of making wires. I’ve never been great with electrical.

Any reason not to skip that process and go with something like the AuxBeam 6 gang switch panel kit?
It’s pre-wired, and about $250 cheaper than the parts for a DIY Bussman RTMR setup (most estimates I saw were $375 for parts). Seems like this would be more than enough for: a lightbar, ditch lights, and a winch as my 3 accessories, yeah?
Am I completely missing something here?

 

[jdevtac]

@jdevtac I read this incredibly detailed tutorial for a DIY Bussman RTMR setup. It was pretty overwhelming - tons of parts to order and what looks like 5+ hours of making wires. I’ve never been great with electrical.

Any reason not to skip that process and go with something like the AuxBeam 6 gang switch panel kit?
It’s pre-wired, and about $250 cheaper than the parts for a DIY Bussman RTMR setup (most estimates I saw were $375 for parts). Seems like this would be more than enough for: a lightbar, ditch lights, and a winch as my 3 accessories, yeah?
Am I completely missing something here?

There’s nothing wrong with buying something like the auxbeam. Many people are happy with it. If you felt it was lacking down the road, you could always go down the rabbit hole and upgrade to just about anything you want. I went with a diy RTMR because I have many crimp tools on hand and was able to source exactly what I wanted to build it out.