MICTUNING Heavy Duty 7 Gang Junction Box Install Help

[Yoda]

OK the brake wiring got me to open up the junction box behind my king pin. I have been it it before to get the reverse light (yellow wire) but not noticed much else. This is the replacement unit I have https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1


For those that have done the install, did you put it back in the same place? I went looking for an install thread but did not find one, but you know I am search impaired

I assume step one is to remove the screws holding the OEM metal box in place and lower it out of the king pin head. The secure the MICTUNING where it was and probably secure the 7way cable. Then as I remove each wire....hmmmm the trailer side wire bundle is secured with the box fitting,,,so how to remove and install one at a time. Tips?

Most looks straight forward. Remove on for the old and install in the new. Example the blue brake wire and emergency brake disconnect power feed (black) I would remove for the Scotch conecctor, install ring terminals and install to the blue wire stud in the MICTUNING

However what did you folks do with the big bundle of negative return wiring (white) under the big (loose again) blue wire nut. One white wire comes from the 7 way cable, the rest go into the trailer wiring harness. I do not see a ground screw in the metal junction box, but it may be hidden. Is the white wire the trailer ground (negative return) to the tow vehicle? Can I install a ground stud outside the MICTUNING? I don't think they will all fit inside the new junction box.

Last question - was there plenty of wire length when you moved the wires over? It looks like I have an inch or two of wire bundle to the left of the existing box.

Thanks for any help or useful links.

Keith

BTW folks if you have an intermittent grounding issue (blinking/flashing trailer lights). look in your junction box for this blue nut and be sure it is tight. On my unit there was a second one below the power bar where the battery connects. I moved those to thier own ground (negative return bar) connected to the trailer frame..

[TucsonJim]

Keith - I realize mine is a travel trailer, but the concept should be the same. I disconnected all the wiring. Then I pulled the wire out of the box. Next I unscrewed the OEM box and attached the Mictuning box I pushed the wires through the grommet on the Mictuning box. Then I trimmed each wire to length, attached a connector and heat shrank it. The Mictuning cable should already have connectors installed. Next, I mounted the connectors onto the stud and tightened them. Finally, I tested the wiring and sealed the box.

[Yoda]

Keith - I realize mine is a travel trailer, but the concept should be the same. I disconnected all the wiring. Then I pulled the wire out of the box. Next I unscrewed the OEM box and attached the Mictuning box I pushed the wires through the grommet on the Mictuning box. Then I trimmed each wire to length, attached a connector and heat shrank it. The Mictuning cable should already have connectors installed. Next, I mounted the connectors onto the stud and tightened them. Finally, I tested the wiring and sealed the box.

Thanks Jim for the pictures.

It looks like there should be room for my 5 negative wires (one from the 7 pin, so 4 in the box where you have 3), so it should work. It will be a week for me to get to this, but making sure I have all the stuff. I am set on heat shrink ring terminals and Ill take lots of pictures. . I was thinking when I cut the old 7 pin cable loose to leave a wire in the junction so I know where the go.. Do you remember the size of the studs - I think they are 10MM but wanted to check. Ill test fit before I make the crimps.

This may should like a dumb question, but how did you test - plug into the truck?

BTW are the negative returns (white wires) from each trailer light circuit? Just curious.

Thanks for your help

Keith

On edit - I happen to glance at some bad reviews on Amazon claiming the wiring was messed up in the plug, So I ohmed all of the connections out. I'm good

[TucsonJim]

Keith - Good idea to leave as much evidence as possible and take lots of pictures during disassembly in order to get it hooked up correctly.

I don't remember the nut size, but I'll be 10mm is probably correct.

For testing, yeah, you can do a plug in to make sure it's working correctly with the truck.

And yes, those should be the light returns.

Jim

[Country Campers]

When I did mine I cut the wire connections in the old box to which kept all of the original wiring in place so all I had to do was connect all of the same wires into the new box. Colors did not help me much, colored blind, so the wife did help and made things easier. Lots of pictures helped as well.

Brian

On edit I found the studs may be 5 mm.

[Yoda]

Thanks for all the tips.........another adventure into the Twilight Zone
Keith

[Scott'n'Wendy]

DON'T assume white is negative. White wires are supposed to be positive in a DC circuit. Black should be negative.....But...being an RV...could be either. Test first. Take several pics with your cell phone before you disconnect the wires. At some point you will be glad you did.

[Scott'n'Wendy]

Colors did not help me much, colored blind,
Brian

Ooooo...you must hate wiring.

[Yoda]

DON'T assume white is negative. White wires are supposed to be positive in a DC circuit. Black should be negative.....But...being an RV...could be either. Test first. Take several pics with your cell phone before you disconnect the wires. At some point you will be glad you did.

Scott - is that a Canadian thing? Just kidding .....I have a friend in Perth where everything is upside down and backwards.

High school electronics class DC positive was always supposed to be red, black was negative, White was earth ground if there was one . Of course back then the wires with a color stripe were rare.. However we all learned to make a simple test pen (12v Light bulb on a stick). It was our first soldering project where I discovered I can't solder Then when we got to the 120V AC chapter we all got confused, that black was always hot and white neutral with green being earth ground. However grounded plugs did not exist. How we all survived with out the gooberment safety's I never know. You were a sissy if you wore a football helmet riding a bike. You were cool for ripped bluejeans and big band aids on the knees, elbows and hands.

You can bet I will be testing everything. Somewhere in that mess is a hot positive that goes to the battery. I think it is the red with white stripe in post #1. Ill test first. I think the second red wire is the L Turn

BTW this is an interesting read on wire colors around the world for AC and DC https://www.electricaltechnology.org...s-nec-iec.html

Makes me wonder how or why the RV industry does not follow any of this??? Seen very confusing when the rest of the industry has set standards NEC, etc.

When I get into it I'll document and post what I find

howson Howard - is it possible to plug the Mictuning into my truck stand alone and verify all of the connections (turn signals, etc), without hurting the truck. I don't want to be setting any error codes.



Thanks Folks

[Cate&Rob]

Yoda

RVIA seems to be in their own world. The claim to follow the NEC for electrical but have applied 120VAC logic to 12VDC wiring . . . thus the white wire color for the “non power” side of the circuit.

Rob

[Scott'n'Wendy]

Makes me wonder how or why the RV industry does not follow any of this??? :

Cuz they don't have to.

[TucsonJim]

Forum members. For discussions on electrical standards that are not specifically related to this thread, please visit the following link:

https://gdrvowners.com/forum/operati...stem-standards

Jim

[howson]

howson Howard - is it possible to plug the Mictuning into my truck stand alone and verify all of the connections (turn signals, etc), without hurting the truck. I don't want to be setting any error codes

Yes.

Apologize for the tardy response -- on the road and there's no WiFi and poor Verizon coverage where I'm located, so participation here over the next several days (7 June - 11 Jun 2023) will be much less than normal.

[Scott'n'Wendy]

On edit - I happen to glance at some bad reviews on Amazon claiming the wiring was messed up in the plug, So I ohmed all of the connections out. I'm good

Always a good idea. Even new parts are built wrong from time to time.

[Jlawles2]

Keith, I cheated a little. I cut off each of the connectors so it would pass out of the box, but I did tape them together so I knew which ones were bundled together. There was just not enough to leave them all connected and in the metal box while making the swap.

I also did similar to Jim but I followed a little bit of home wiring. I made all of the wires the same length in case one of the ends gets damaged I have a little spare length. I don't remember the nut size, but it's 8mm, 10mm, 5/16" or 3/8". It's a common size and I did use a deep socket when doing the tightening on my favorite 1/4" ratchet (aka the aluminum thread stripper).

No need for heat shrink insulated terminals. Note in Jim's pic, none of the pig tail ring terminals are insulated in any way. All of the terminal studs are in their own little alley between raised plastic walls. If needed you can add a nut to the negative one and spit out the ring terminals so you are not playing with 6 at one time. (hint hint)