Jeep brake harness

[bevandtomH]

I won’t tell you I understand this, but here is the story.
We have a 2017 Jeep JKU 4dr. Sahara.
I set up the base plate, and wired the Jeep with the recommended Hopkins brake light kit. We’ve put a few thousand miles on the MH and tow, no issues.

Recently, we went out one night for some local entertainment, and on the drive home, my Jeep’s brake, ABS, and anti-skid went off with sounds and lights.
I decided to slow down and got home safely.
It was recommended by my dealer, since the brake light came on, to have it towed in for service.
Next day I got a call from their service desk that the tech wanted to talk to me. When I got there, his first question was; “You flat to this behind your MH, correct?”
Me, “yes, why?”
What he said next confused me.
He grabbed his laptop and plugged it into my Jeep.
He said, “See that?”
Me, “What?”
Tech, “Your after market harness is only communicating so far with the Jeeps diagnostic systems and does not see your brakes, ABS, or anti-skid. It recognizes everything up to point, then freaks out.
I asked him why I had not seen it before after 10k miles on the Jeep. He really did not have a reason other than a shrug.
My proof, I guess, was in all the fault codes thrown related to what I am experiencing.
His recommendation was to replace the Hopkins with the Jeep Approved Flat Tow Harness kit. Which I did.
Once done, he brought his laptop out to my Jeep and plugged into the OBDII, no faults. Everything works as it should.
Our recent trip was flawless in towing, and I’ve not had any issues driving.
I called Hopkins during this and had a conversation about what was going on. The CS Rep was skeptical that their harness could be the issue, who knows. But I can say, I have no issue with Hopkins, nor their CS, they were great.
On our recent trip, a fellow camper had a 2019 JKL and was having similar issues. I told him the same story. After my experience, I did not like the way his dealer wired his. What do I know, right?
For what is is worth, hopefully if you see this, you will know what the solution may be.

[dp7]

Originally Posted by bevandtomH

I won’t tell you I understand this, but here is the story.
We have a 2017 Jeep JKU 4dr. Sahara.
I set up the base plate, and wired the Jeep with the recommended Hopkins brake light kit. We’ve put a few thousand miles on the MH and tow, no issues.

Recently, we went out one night for some local entertainment, and on the drive home, my Jeep’s brake, ABS, and anti-skid went off with sounds and lights.
I decided to slow down and got home safely.
It was recommended by my dealer, since the brake light came on, to have it towed in for service.
Next day I got a call from their service desk that the tech wanted to talk to me. When I got there, his first question was; “You flat to this behind your MH, correct?”
Me, “yes, why?”
What he said next confused me.
He grabbed his laptop and plugged it into my Jeep.
He said, “See that?”
Me, “What?”
Tech, “Your after market harness is only communicating so far with the Jeeps diagnostic systems and does not see your brakes, ABS, or anti-skid. It recognizes everything up to point, then freaks out.
I asked him why I had not seen it before after 10k miles on the Jeep. He really did not have a reason other than a shrug.
My proof, I guess, was in all the fault codes thrown related to what I am experiencing.
His recommendation was to replace the Hopkins with the Jeep Approved Flat Tow Harness kit. Which I did.
Once done, he brought his laptop out to my Jeep and plugged into the OBDII, no faults. Everything works as it should.
Our recent trip was flawless in towing, and I’ve not had any issues driving.
I called Hopkins during this and had a conversation about what was going on. The CS Rep was skeptical that their harness could be the issue, who knows. But I can say, I have no issue with Hopkins, nor their CS, they were great.
On our recent trip, a fellow camper had a 2019 JKL and was having similar issues. I told him the same story. After my experience, I did not like the way his dealer wired his. What do I know, right?
For what is is worth, hopefully if you see this, you will know what the solution may be.

I used the mopar harness on my 2017 JK. It was a little more difficult to install than the aftermarket ones, but after 20,000 towed miles, no issues. Plus, Jeep cannot question any future warranty claim because non-mopar wiring was used.

[FIRE UP]

bevandtomH,
Well, at this point in time, all I can tell you is, we have a '15 JKUR and, I wired it with the Hopkins harness in the onset of setting the Jeep up for towing, about 3+ years ago and, we've got about 30K miles and 3+ years of towing and not one single issue with the Hopkins unit. And, as you stated and or asked, WHY DIDN'T THEY HOPKINS UNIT CAUSE ISSUES FOR THE FIRST 10,000 MILES OF TOWING? The point is, IT DIDN'T!

There are plenty of members on here that utilize that Hopkins unit and have had no issues. Just EXACTLY why your Jeep hiccupped, even the tech doesn't know. He simply suggested to buy MOPAR parts. You went 10K miles on the Hopkins unit. How long might, I say MIGHT, you go on the Mopar unit before you get the same hiccup? Who knows?

My nephew's wife took their brand new Jeep JLUR to work the other day, with only about a couple hundred miles on it and, guess what, IT WOULD NOT SHUT OFF when she got to work!!!!! How about that!
Scott

[Alan_Hepburn]

Are you talking about the harness to connect the RV's lights to the Jeep's lights? My understanding is that it includes a set of diodes to prevent back-feeding the Jeep's system, so there should be no interaction between the vehicles.

[FIRE UP]

Originally Posted by Alan_Hepburn

Are you talking about the harness to connect the RV's lights to the Jeep's lights? My understanding is that it includes a set of diodes to prevent back-feeding the Jeep's system, so there should be no interaction between the vehicles.

The Hopkins 56200 tow harness is the one used for utilizing the Jeeps original tail lights as toad lights. Yes, it will have maybe some form of diodes in it (although I didn't really look for them when I installed mine about 3 years ago). But, diodes can short out. It's rare that it happens but, it does happen. The can fail (short) open or, they can fail closed. In one way, NO voltage gets through. In the other way, it can travel both ways, NOT GOOD. Now, just what happened to the OP's Jeep, well, we'll probably never know. Jeep just told him to put the Mopar harness in, AFTER he'd already driven 10K miles with the Hopkins.
Scott

[Alan_Hepburn]

I JUST installed the Hopkins harness in our 2017 JKU, and the diodes are in a box that ends up behind the driver's side tail light housing. I haven't had a chance to test it yet, but I'm assuming the diode pack will work to isolate the system.

[bevandtomH]

I think Fire Up is probably correct on what may have happened. There could be a short in the Hopkins wiring. Who knows.
With so many using their kit, my situation would seem isolated. IMO.
Could it happen with the Jeep harness too? Sure.
But I hope not.
Tom