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Quick Reference-Tow Package - Fuses

khemist000

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Not sure if this thread is still active, but I've got a harness / fuse question...

Our 2018 JL Sahara supposedly came with the factory tow harness, however we tried to hook up our 1968 Shasta compact to it and only had running lights, then nothing, and our tail light stayed on.

We took a peek at the fuse box and every single trailer fuse was not present. Is this normal? If not should I replace these fuses? If I should replace them, are they readily available at any auto parts stores?

Thanks!
 

Rhinebeck01

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@khemist000

Need to know if your JLU did have the tow harness installed at the factory.. My guess is it did not.

You say your 2018 JLU "supposedly came with the factory tow harness " .... Does your JLU have the 4 Aux switches on the dashboard that come with the factory tow package? If it does then you JL, did leave the factory with the factory installed tow package.

Please post back if you have the Aux switches..

A n easy way to tell what exactly your JLU left the factory with is to click on this link and when you get to to the next page, just go and add your VIN# to the URL and then hit enter.
Your Equipment List will tell you what all you have in your build. It will list the tow package if your JL had the tow package installed at the factory.
https://www.jeep.com/webselfservice/BuildSheetServlet?vin=
 

khemist000

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@khemist000

Need to know if your JLU did have the tow harness installed at the factory.. My guess is it did not.

You say your 2018 JLU "supposedly came with the factory tow harness " .... Does your JLU have the 4 Aux switches on the dashboard that come with the factory tow package? If it does then you JL, did leave the factory with the factory installed tow package.

Please post back if you have the Aux switches..

A n easy way to tell what exactly your JLU left the factory with is to click on this link and when you get to to the next page, just go and add your VIN# to the URL and then hit enter.
Your Equipment List will tell you what all you have in your build. It will list the tow package if your JL had the tow package installed at the factory.
https://www.jeep.com/webselfservice/BuildSheetServlet?vin=
Sadly, no Aux switches, which was another bummer, but willing to live without that. I'll check my VIN now and report back. Thanks for the reply!
 

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khemist000

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Seems like a no on the VIN check ?.

Should I install these fuses myself?

I'm now pretty nervous about killing the electronics with the trailer. Also really need to track down the issue. The magnetic temporary lights will be our stop-gap for the season if the dealer can get those working, but I would love to get the 7 pin socket working correctly. I can't imagine the issue is trailer side since it worked fine with our Juke (and fine with the previous owners car) AND we just had the trailer inspected in February (I'm guessing they checked wiring and proper grounding, etc but I'm just assuming here).

I've got an appointment next Tuesday to get the jeep looked at, but I'm just curious for my own education and understanding of our new vehicle. Loving it otherwise!
 

Rhinebeck01

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Seems like a no on the VIN check ?.

Should I install these fuses myself?

I'm now pretty nervous about killing the electronics with the trailer. Also really need to track down the issue. The magnetic temporary lights will be our stop-gap for the season if the dealer can get those working, but I would love to get the 7 pin socket working correctly. I can't imagine the issue is trailer side since it worked fine with our Juke (and fine with the previous owners car) AND we just had the trailer inspected in February (I'm guessing they checked wiring and proper grounding, etc but I'm just assuming here).

I've got an appointment next Tuesday to get the jeep looked at, but I'm just curious for my own education and understanding of our new vehicle. Loving it otherwise!
@khemist000

NO, you do not want to place those fuses!

Since your tow harness since it is not a factory installed tow harness/package does not use those fuses in the power distribution center(PDC).

IF you indeed have the Mopar harness installed by self or the dealer (not factory installed), then the fuses for them are not in the PDC.... the relays in regard to your tow harness are in a small box mounted on the firewall by the brake booster on the driver's side...... the fuses are in small inline fuse holders hanging from the harness wires coming from the small box mentioned. You should find the harness running along the top of the firewall going towards the passenger side.... the fuses should be more towards the passenger side.

.
 

khemist000

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@khemist000

NO, you do not want to place those fuses!

Since your tow harness since it is not a factory installed tow harness/package does not use those fuses in the power distribution center(PDC).

IF you indeed have the Mopar harness installed by self or the dealer (not factory installed), then the fuses for them are not in the PDC.... the relays in regard to your tow harness are in a small box mounted on the firewall by the brake booster on the driver's side...... the fuses are in small inline fuse holders hanging from the harness wires coming from the small box mentioned. You should find the harness running along the top of the firewall going towards the passenger side.... the fuses should be more towards the passenger side.

.
Gotcha. Yeah, I thought the harness was factory so since it's not, I have no idea when, how, or by whom it was installed.

Fuses aside... Would you have any idea of what could be causing me to melt the tow module when I connect the 7 pin wire from my camper trailer to the Jeep? This past weekend when we connected our trailer, smoke poured out of our passenger side tail light, frying the tow module for the 2nd time. I would expect fuses or something like that would prevent that from happening (sadly, I'm very uneducated about electronics or electrical engineering, so this is purely assumption).

The only lead I have so far is that the 7 pin tester I used after the dealer replaced the tow module was showing different lights on the tester than were coming out of the jeep. Basically when the right turn signal was on, the tester showed the Auxiliary brakes or 12v was showing in the spot where running lights should be, etc (I forget the actual mappings I just know they didn't correspond to the correct lights on the tester). This leads me to think that the 7 pin receptacle on the jeep was just plain wired wrong...
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