Cooltech JK Wiring Harness and Invisibrake on 2016 Jeep JKU

[mdntblu]

Originally Posted by Steve-W

The diodes you have will work (same ones I am using). From what you have said it sounds like you did not splice the wires but used two “Y” connectors to connect the three 4 flats together. That being the case on the 4 flat after your “Y” going to the CT harness 4 flat you will need to cut only the green & yellow wires and add the diodes (you will need two). The wire G or Y from the “Y” will connect to one of the “In” connections on one diode. The “out” will then connect to the cut wire going to the CT harness. The second “In” on the diode will remain unused, tape or otherwise insulate this terminal. You will do the same with the second diode on the other G/Y wire.

Does your Jeep have LED or incandescent rear lights. If LED from some info I’ve come across there may be another factor playing into this.

A brake light relay will also work rather than diodes.

Ok I'll have to dig deeper into that scenario you listed above. I'm not quite grasping the concept but all my wiring is still exposed and not tied down quite yet so it's easy for me to manipulate it.

My Jeep has standard incandescent tail lights. No LED's.

Since I already have the diodes I'm kinda wanting to go that route unless you think the brake light relay is easier to install and better for this purpose.

After doing some more playing today ----


I removed the 15amp fuse for the CHMSL (Fuse M1) and then when I got in my RV and hit the brakes I didn't have the issue where it sticks.
https://imgur.com/SpAm2MX see this video.

However after unhooking everything and getting ready to move the Jeep away from the RV when I hit the brakes the Invisibrake would go on and stay on for 20secs.

[mdntblu]

Originally Posted by Alan_Hepburn

If the CoolTech harness in question is the one they sell that puts a switch under the passenger seat, then it should completely isolate the Jeep's lights. The switch is spliced in to the Jeep's wiring harness and it supplies power to the Jeep's brake/tail lights from either the Jeep or the RV, but not both. If the Jeep's brake pedal is activating the brake lights when the switch is in the "RV" position then this harness is not installed properly.

It’s the JK version not the JL. Only the JL one has the different installation method and the switch.

[mdntblu]

Another interesting tidbit of info.

So if the CHMSL fuse is out and the RV is plugged into the Jeep with the umbilical cord it works perfectly. If the key is turned to on and I press on the brake inside the Jeep (even with it still hooked up to RV) it activates the Invisibrake for 20secs. Once I turn off the key it stops.
But then if the umbilical cord is removed and the fuse is still out it activates the IB. Super strange behavior.
So for my upcoming trip (unless I figure out the issue before then) I’ll be removing the IB fuse for normal driving and putting it back in for towing.

[mdntblu]

Originally Posted by Steve-W

The diodes you have will work (same ones I am using). From what you have said it sounds like you did not splice the wires but used two “Y” connectors to connect the three 4 flats together.

Not sure where you get 2 Y connectors. There are not really any Y connectors. I just spliced the wires.

Originally Posted by Steve-W

That being the case on the 4 flat after your “Y” going to the CT harness 4 flat you will need to cut only the green & yellow wires and add the diodes (you will need two). The wire G or Y from the “Y” will connect to one of the “In” connections on one diode. The “out” will then connect to the cut wire going to the CT harness. The second “In” on the diode will remain unused, tape or otherwise insulate this terminal. You will do the same with the second diode on the other G/Y wire.

I'll see if I can follow this and install them like this.

[Steve-W]

From what you are reporting as far as operation something is miswired. It makes no sense as to what is happening with the CHMSL fuse in/out. The CHMSL signal is completely separate from the normal brake lights. If it wasn't it would flash with the turn signals. It should have no bearing on toad lighting wiring.

If it were me I would ditch the CT harness and just use the diodes (you will need 4) you have to the brake & tail lights, that is a simple configuration. again you will still need a brake light relay so that the toad brakes do not override the turn signals. The CT harness just seems to be over complicating the task.

Wiring print for diodes with Invisabrake.

Brake light relay wiring.

[mdntblu]

Originally Posted by Steve-W

From what you are reporting as far as operation something is miswired. It makes no sense as to what is happening with the CHMSL fuse in/out. The CHMSL signal is completely separate from the normal brake lights. If it wasn't it would flash with the turn signals. It should have no bearing on toad lighting wiring.

If it were me I would ditch the CT harness and just use the diodes (you will need 4) you have to the brake & tail lights, that is a simple configuration. again you will still need a brake light relay so that the toad brakes do not override the turn signals. The CT harness just seems to be over complicating the task.

Wiring print for diodes with Invisabrake.

Brake light relay wiring.

Yeah I was trying to not have to do as much installation using the CT harness but man the amount of time I've spent dealing with it has been insane. You're right just doing the standard 4-flat wiring with diodes to the back of the Jeep would have been way simplier at this point. I spent almost $200 on that harness and not sure I can return it for my money back which sucks.
Crazy thing is I had the same setup on my last Jeep (however I didn't install it, it was installed when I bought it) and it worked fine. I wonder if it had brake light relay installed and diodes. I asked the new owner (as he knew I was having troubles with it) if he sees diodes in the back lights and he couldn't find any. But I never had any issues with that system.

[mdntblu]

Originally Posted by Steve-W

The diodes you have will work (same ones I am using). From what you have said it sounds like you did not splice the wires but used two “Y” connectors to connect the three 4 flats together. That being the case on the 4 flat after your “Y” going to the CT harness 4 flat you will need to cut only the green & yellow wires and add the diodes (you will need two). The wire G or Y from the “Y” will connect to one of the “In” connections on one diode. The “out” will then connect to the cut wire going to the CT harness. The second “In” on the diode will remain unused, tape or otherwise insulate this terminal. You will do the same with the second diode on the other G/Y wire.

I ended up using 2 diodes and doing what you said and it solved the problem.
I know you also said a brake lite relay kit will do the same thing. I didn't have the relay kit but I'm guessing that I might need to do that as well. Because I'm wondering if the turn signals on the Jeep will be jacked up while braking. I'll have to test that out and see. So I may have done diodes for no reason but at least I know that it was just feeding back and causing that problem.

Thanks for all your help. Maybe this thread will help someone else in the future.

[Steve-W]

Glad I could help. Yes most likely you will need the BL relay so the brake lights don't over ride the turn signals.

Noticed you're in Corona. I'll be out that way next month. I worked for a company in Irvine for 32 years, I was a field Engineer so I worked from my home in PA.

[mdntblu]

Originally Posted by Steve-W

Glad I could help. Yes most likely you will need the BL relay so the brake lights don't over ride the turn signals.

Noticed you're in Corona. I'll be out that way next month. I worked for a company in Irvine for 32 years, I was a field Engineer so I worked from my home in PA.

Yea I will need BL relay. Just hooked the Jeep up to my Expedition and it does over rise the turn signals. Ugh. Well at least the braking controller is working correctly.

Yeah Corona is just over the (currently snowy) hills from Irvine.

[Steve-W]

At least you now have a full solution on the horizon. You can use a standard automotive relay available at any any auto parts store, about 1/2 the $ of the Roadmaster.

You said you were using the a dash indicator in the MH to show brake application. Keep in mind when you add the brake light relay depending upon where you break the circuit you may need an auxiliary brake light switch to retain that function (check Roadmaster's fit chart). That was necessary in my Cherokee the way the wiring is done from the factory.

I wonder what the CT harness is supposed to accomplish other than a very costly no splice "T" connection to the lights.

I never saw those hills in any color but brown, it's been crazy weather this year. We were 70 a few days ago 30 at the moment.

[mdntblu]

Originally Posted by Steve-W

At least you now have a full solution on the horizon. You can use a standard automotive relay available at any any auto parts store, about 1/2 the $ of the Roadmaster.

You said you were using the a dash indicator in the MH to show brake application. Keep in mind when you add the brake light relay depending upon where you break the circuit you may need an auxiliary brake light switch to retain that function (check Roadmaster's fit chart). That was necessary in my Cherokee the way the wiring is done from the factory.

I wonder what the CT harness is supposed to accomplish other than a very costly no splice "T" connection to the lights.

I never saw those hills in any color but brown, it's been crazy weather this year. We were 70 a few days ago 30 at the moment.

I ended up getting the Roadmaster brake light relay on Amazon (think it was cheaper than etrailer).

But throughout the process I kept checking things and it seemed fine. I buttoned everything up and had my son hit the brakes without the key, nothing. Then I turned on the key and he hit them and they turned on. No CHMSL though. I was pretty tired from installing all of it and yes I ran a wire for motorhome brake light LED but I didn’t actually hook it up yet. Just taped it off.

Then I put the Jeep out of the driveway and cleaned up.

I went back out and checked it and noticed that when the key is on the brake lights stay on. Turn key off they turn off. Now im really puzzled and we are heading out of town in a few days.

[mdntblu]

So because I thought I installed something incorrectly, I took the brake light switch plug back off, rechecked all the wiring and then ended up putting it back to stock with the brake light relay completely removed. And the Jeep is still keeping the brake lights on (only when the key is in run). Which makes no sense. Before I installed anything the brake lights would turn on when the key was off and now with it being setup with how it was before installing the brake light relay I would think they would operate the same way but they don't.

Now I'm really baffled and this sucks because technically I shouldn't even be driving the Jeep with this condition with having stuck on always brake lights.

Interesting thing is the CHMSL doesn't work anymore either. Even when I turn on the key and the brake lights turn on. Sooooooo strange. This has been the most frustrating sequence of events for me.

Originally Posted by Steve-W

I wonder what the CT harness is supposed to accomplish other than a very costly no splice "T" connection to the lights.

Yeah I wonder what this actually does for me. Only thing I can see that it does is when the running lights are on, on the RV, the running lights are also on for the Jeep (License plate, front orange lights).

[mdntblu]

Ok so after sitting here very frustrated and not knowing what to do next I took the brake light switch off the arm. It seemed to be fine but the fact that weird things were happening my only other quick option was to head over to AutoZone and pick up a new brake light switch.
So with the brake light relay completely removed I hooked up the new brake light switch and what do you know everything’s working correctly.
Then I put the relay back on and now it’s working as it should. Wow what an experience.
I hope I’m done with this now and no more issues.

[Steve-W]

Crazy sequence of events thats for sure. Always fun when something fails in the middle of a repair/mod. I seen it many times in my professional career. It always makes for an interesting day.
Good luck and have a safe trip were heading out as well.