Emergency brake switch wiring question

[DanandDaphne]

I accidentally pulled on the emergency brake switch wires and so I checked to make sure it was still ok. I pulled the cover off the junction box mounted up under the loft frame and found that one of the two wires was pulled loose. The thing is there is no crimp connector on any of the lugs that it could have pulled out of unless they put two wires into one connector.

The connector that is still connected is connected to the positive lug in the box the other is just a bare wire both are black.

Does anyone have the schematics for this junction box or happen to know which lug this wire should be connected to?

Thanks in advance for any help with this.

[DanandDaphne]

Here's a picture. The wire is shorter than the other one so it was probably one of the first two or three either blue or brown maybe.

[Centex]

The two wires to the emergency disconnect 'pull pin' go to the 12V+ battery charging stud and the brakes stud. It doesn't matter which wire on which stud.

When the pin is pulled, the circuit is closed, sending constant 12V+ from the battery through pull-pin switch, thence to the brakes causing activation.

Here it is on my 2022 5.0 just FYI

Hope that helps.

[Centex]

Looking at your pic, it appears the loose wire was crimped in a single terminal along with another (blue?) wire on the brake stud.

I suggest you take all of the terminals off that stud and ensure all are well-crimped / tight on the wire.

I normally dislike multiple-wires in one crimp connector, but in this case I can see an argument in support of crimping the E-brake switch with the trailer-side brake wire: IF the nut on the stud becomes loose, there's still continuity to the brakes if the double-wire crimp is good.

IMO to make a 'good' double wire crimp you need to expose extra length of stripped conductors so you can twist the exposed strands of both wires tightly together before inserting in the crimp connector. It appears that was not done by ETI and I'm not sure you have enough slack in the wires to do that. Maybe you do if you re-orient the crimp connector 'down' so its open end is closer to the short e-switch wire.

Good Luck!

[DanandDaphne]

Thanks Centex, I knew you would have the answer!

I'm sure you're right about the blue connector the way that it is bent out just a bit, it didn't take much to pull it out so it was never in there properly. My guess is that it was barely connected.

Yes that makes sense for crimping the wires together and I was planning to check the other brake connections once I knew for sure which ones they were. The other wire on the break away switch is poorly crimped so I'm going to redo it as well. I really prefer uninsulated crimp connectors because you can get a more solid crimp. Then insulate with good quality heat shrink tubing if necessary.

Then I'll test the breakaway switch to make sure it's working as it should once it's all hooked back up.

[DanandDaphne]

Well got it back together, thanks again Alan.

After replacing the ring connectors on the breakaway switch wires, I got my volt meter and as it should be I get no voltage between ground and the brake connection lug. After pulling the breakaway cable out I get 12.68V. I don't know what it should be but I think that sounds about right to me, the brake magnets I think would bring the voltage down from the full battery charge.

[Chamberman]

You may want to replace the crimp connectors on several of those wires. In your picture you can see that a few of the wires were improperly crimped and this resulted in the split ring spreading far apart. You can see the split ring spread far apart in the picture I attached. The red arrows are pointing to the ring terminals that the insulator had slipped down on leaving the spread out split ring visible. This leaves the majority of the wire floating uncrimped and poorly attached. Its possible several more of these wires may just pull out of the crimp terminal with minimal force.

[Chamberman]

Better picture

[DanandDaphne]

Originally Posted by Chamberman

Better picture

good eye, I was thinking I would remove the destroyed insulation from them and hit them with solder. My guess they were using a crimping tool for non insulated connectors because they are all destroyed some have fallen off the connector and are hanging on the wire.

[Chamberman]

Originally Posted by DanandDaphne

good eye, I was thinking I would remove the destroyed insulation from them and hit them with solder. My guess they were using a crimping tool for non insulated connectors because they are all destroyed some have fallen off the connector and are hanging on the wire.

I've got several wire crimpers and I've never been a big fan of using the "dimple" style crimper on these insulated terminals. Even if you turn the insulated terminal over and put the dimple on the bottom opposite of the split you can still over-compress and damage the wire crimp. Crimping from the top side, as yours are crimped, you must be mindful of how far you go. Too much force and you cause damage and the split ring spreads out and the insulator gets damaged and becomes loose.

[Centex]

Attention to a few details can make the difference between robust long-term solderless connections and troublesome connections IME.

Tightly twisting conductor strands is the first step for me, that helps ensure the conductor retains a round shape in the connector barrel rather than the strands 'parting and flattening' inside the barrel when crimped. with some wire that involves stripping an excess length to provide grip for twisting, then clipping the twisted conductor to the correct barrel-length.

I happen to prefer the 'dimple' type tool, but one must ensure the connector barrel is oriented so the dimple is opposite the seam in the barrel, whether brazed-seam or not. ETI obviously did not do that in the pictured crimps, so they are far from as good as they could be.

Moderation with the squeezing force is also important IME. The object is to end up with a still-round barrel with an adequate dimple to hold the wire firmly. Over-ambitious squeezing can easily deform the barrel resulting in a less secure connection. That's also evidenced in the pictured crimps IMO.

With good quality insulated terminals I've found I can make consistently nice and firm 'dimple' crimps without the insulating sleeve suffering damage.

YMMV, Have Fun!

my favorite crimper, a vintage VACO No. 1902 inherited from my dad, still makes great dimple-crimps