Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
RV Trip Planning Discussions

Go Back   iRV2 Forums > MOTORHOME FORUMS > Toads and Motorhome Related Towing
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
 
Thread Tools Search this Thread Display Modes
 
Old 03-11-2021, 07:09 PM   #1
Senior Member
 
Isaac-1's Avatar
 
Join Date: Jun 2016
Location: SW Louisiana
Posts: 7,294
Cherokee flat tow harness DIY?

I have recently installed a Cherokee flat tow wiring harness on our 2017 Cherokee Overland edition, and for some reason it is tripping the check engine light. I am now at the point of pulling everything back apart and rechecking my work, I have also tried asking over at the Jeep Cherokee Club forum, unfortunately all of the answers there so far seem to be from people that say you should have taken it to a dealership, or similar less than helpful stuff.


So question #1, when the flat tow harness is working properly, does the power steering continue to power the steering wheel? The way mine is wired, when it is activated the steering wheel feels stiff, like when the car is normally off.


Now down to what is happening, I installed per the published instructions, only modification I did was add an inline switch in addition to the under hood fuse holder, so that I don't have to pull the fuse each time I want to go back to normal drive mode, but for consistency I will say insert / remove fuse from now on.


If I turn off the car, wait a minute for the gauges to go dark, then flip the Red center console switch up, wait a minute, flip it back down, and start the car I get a check engine light, OBDII scanner shows code u0131 Lost Communication with Power Steering module A


If I clear codes, turn car off, wait a minute for gauges to go dark, flip red switch up, then insert the under hood fuse, I will hear a brief whirrr sound, at the same time the gauges will light up again, if I then remove the fuse, flip red switch off wait a minute (or not wait a minute) start the car I get check engine again, this time I get the u0131 as mentioned above, but also get u0101 Lost Communication with TCM.


I am 99% sure I have the CAN block wiring done right, attached is a photo of the wiring for the one I moved to the new block (yellow with brown trace, and yellow wire). I am 95%+ I cut the correct wire under the fuse panel, though I plan to pull that back apart tomorrow and double check. Colors were correct and position matched the relative position in the photo in the instruction, I triple checked before cutting, but who knows.


If anyone has any ideas, please share. It seems the Can bus is either not going to sleep before I flip the red switch (I have waited 2-3 minutes after stopping the engine, opening and closing the door) and I still get these results. I don't understand my inserting / removing the fuse causes a TCM error, or why upon inserting the fuse the gauges light up again.


Ike
Attached Thumbnails
Click image for larger version

Name:	Can-block.jpg
Views:	21
Size:	348.7 KB
ID:	320996  
__________________
2002 Safari Trek 2830 on P32 Chassis with 8.1L w/ 400 watts solar 420Ah LiFePo4
2017 Jeep Cherokee Overland & 2007 Toyota Yaris TOADs with Even Brake,
Demco Commander tow bar and Blue Ox / Roadmaster base plates
Isaac-1 is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 03-11-2021, 08:15 PM   #2
Senior Member
 
Join Date: Sep 2020
Location: Houston Area
Posts: 311
Check your ground wires. Coach to toad, wire harness to ground if it has a ground wire. Bad grounds can cause numerous stange things to happen.
ROUGHRIDER3 is offline   Reply With Quote
Old 03-11-2021, 08:21 PM   #3
Senior Member
 
Isaac-1's Avatar
 
Join Date: Jun 2016
Location: SW Louisiana
Posts: 7,294
There is only one added ground wire to the flat tow harness and it connects to an existing under hood ground point. Also the relay that it grounds is clicking as one would expect.
__________________
2002 Safari Trek 2830 on P32 Chassis with 8.1L w/ 400 watts solar 420Ah LiFePo4
2017 Jeep Cherokee Overland & 2007 Toyota Yaris TOADs with Even Brake,
Demco Commander tow bar and Blue Ox / Roadmaster base plates
Isaac-1 is offline   Reply With Quote
Old 03-11-2021, 08:34 PM   #4
Senior Member
 
Bikinjim's Avatar
 
Join Date: Jan 2015
Posts: 342
Yes, when the flat tow harness is engaged for towing the steering wheel should turn easy just like when the engine is running. If it is stiff, the steering has not been activated and you will not have wobble mitigation enabled. Something is wrong in the installation or there is a problem with the flat tow harness itself if the steering does not turn easy when in tow mode. I would focus on the under hood portion of the install as the cabin interior installation serves only to isolate the CANBUS from the steering system when in tow mode, that portion of the install does not affect the actual powering up of the steering.
__________________
Jim and Shelia
2017 Tiffin Allegro RED 37PA
2018 Chevy Equinox
Bikinjim is offline   Reply With Quote
Old 03-11-2021, 09:07 PM   #5
Senior Member
 
Isaac-1's Avatar
 
Join Date: Jun 2016
Location: SW Louisiana
Posts: 7,294
Thanks, we are both thinking the same way, though it still does not explain the check engine light for just turning the red switch on and off while the gauges display is dark a minute or more after turning off the engine. I will plan on pulling the fuse panel apart and double checking it again in the morning, once I get that bit sorted I will go back to dealing with the red switch check engine light issue.
__________________
2002 Safari Trek 2830 on P32 Chassis with 8.1L w/ 400 watts solar 420Ah LiFePo4
2017 Jeep Cherokee Overland & 2007 Toyota Yaris TOADs with Even Brake,
Demco Commander tow bar and Blue Ox / Roadmaster base plates
Isaac-1 is offline   Reply With Quote
Old 03-12-2021, 05:14 AM   #6
Senior Member
 
Bikinjim's Avatar
 
Join Date: Jan 2015
Posts: 342
Ike, I installed the harness myself on my 2015 Cherokee Trailhawk. I installed it the way Jeep said to first to make sure I had it working correctly then immediately modified it to avoid fooling with the fuse. Since my Tiffin has an ignition switched 12 volt pin in the trailer connector I used it for the charge line to also power the flat tow harness. I connected the charge line directly to the harness (instead of connecting the harness to the Cherokeeís 12volt power at the fuse box) and also to the Cherokeeís battery through a diode (with the diode oriented so that current would flow into the battery for charging the battery but would allow power to flow from the battery to the harness). This resulted in automatically powering up the harness when the Motorhome was running and powering it down when it was not. I just had to make sure I threw the console switch before starting the Motorhome with the umbilical connected and after turning off the Motorhome but before starting the Cherokee. The harnessís console switch purpose is only to isolate the CANBUS so that the check engine light and code are not set. Itís no big deal if you get the sequence wrong and they get set after towing as the light will go out on its own after a few ignition cycles, or of course if you clear the code with your OBDII code reader. But as I said I wouldnít worry about the code and light part until you get the active part of the harness working correctly. Once that is done the code and check engine light side may also work normally at that point. You will find that once it is functioning properly, the steering will turn easily immediately after inserting the fuse (or the switch you added). The steering will continue to turn easily for about 10 minutes after you remove the fuse (or throw your switch) or until you turn on the Cherokeeís ignition. Good luck.
__________________
Jim and Shelia
2017 Tiffin Allegro RED 37PA
2018 Chevy Equinox
Bikinjim is offline   Reply With Quote
Old 03-12-2021, 05:36 AM   #7
Senior Member
 
Isaac-1's Avatar
 
Join Date: Jun 2016
Location: SW Louisiana
Posts: 7,294
I am not sure what is going on in the under hood part yet, but as to the red switch setting a power steering lost communication code, now that I have slept on it, the only thing that seems to make sense to me is that the switch is getting flipped before the can bus is going to sleep. Or that something is waking the can bus up while the switch is flipped. I just don't know what that could be, it should probably be noted that this is an Overland edition with all the bells and whistles, tech package, etc.


Can anyone think of an easy way to confirm the CAN bus is asleep before flipping the red switch other than just the gauge display going black?


thanks
__________________
2002 Safari Trek 2830 on P32 Chassis with 8.1L w/ 400 watts solar 420Ah LiFePo4
2017 Jeep Cherokee Overland & 2007 Toyota Yaris TOADs with Even Brake,
Demco Commander tow bar and Blue Ox / Roadmaster base plates
Isaac-1 is offline   Reply With Quote
Old 03-12-2021, 06:00 AM   #8
Senior Member
 
Bikinjim's Avatar
 
Join Date: Jan 2015
Posts: 342
Waiting until the dash went dark always worked for me. Never had a light after waiting until it went dark, thew the switch immediately after that.
__________________
Jim and Shelia
2017 Tiffin Allegro RED 37PA
2018 Chevy Equinox
Bikinjim is offline   Reply With Quote
Old 03-12-2021, 06:04 AM   #9
Senior Member
 
Isaac-1's Avatar
 
Join Date: Jun 2016
Location: SW Louisiana
Posts: 7,294
I am thinking maybe a multimeter reading voltage on the CAN bus pins on the OBDII port to indicate when the can bus is asleep.
__________________
2002 Safari Trek 2830 on P32 Chassis with 8.1L w/ 400 watts solar 420Ah LiFePo4
2017 Jeep Cherokee Overland & 2007 Toyota Yaris TOADs with Even Brake,
Demco Commander tow bar and Blue Ox / Roadmaster base plates
Isaac-1 is offline   Reply With Quote
Old 03-12-2021, 12:27 PM   #10
Senior Member
 
Isaac-1's Avatar
 
Join Date: Jun 2016
Location: SW Louisiana
Posts: 7,294
Problem mostly solved, found wiring fault going to the under hood relay, now steering stays powered when fuse is connected.


As to the red switch throwing power steering codes, it seems this car takes 3-4 minutes for the can bus to go to sleep, don't know why yet, but it is well after the gauges go dark, I will experiment more on this later. Perhaps there is a stay awake setting somewhere in the settings menu.
__________________
2002 Safari Trek 2830 on P32 Chassis with 8.1L w/ 400 watts solar 420Ah LiFePo4
2017 Jeep Cherokee Overland & 2007 Toyota Yaris TOADs with Even Brake,
Demco Commander tow bar and Blue Ox / Roadmaster base plates
Isaac-1 is offline   Reply With Quote
Reply

Tags
tow, diy, cherokee



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Jeep Cherokee Flat Tow Kit DIY? Isaac-1 Toads and Motorhome Related Towing 4 02-26-2021 10:42 PM
Broke my 2016 Jeep Cherokee installing flat tow harness gary_l Toads and Motorhome Related Towing 4 10-17-2020 11:53 PM
2019 Jeep Cherokee Doesnít Need Flat Tow Wiring Harness LarryinID Toads and Motorhome Related Towing 12 04-15-2019 12:36 PM
Flat Tow Wire Harness for 2017 Jeep Cherokee Trailhawk barryvo1 Toads and Motorhome Related Towing 3 02-03-2018 06:28 AM
Flat tow wiring harness for 2017 Grand Cherokee Trailhawk Clements02 Toads and Motorhome Related Towing 9 03-19-2017 10:38 PM

» Featured Campgrounds

Reviews provided by


All times are GMT -6. The time now is 05:02 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2022, vBulletin Solutions, Inc.