Trailer Tow Fuse Box Location

[SFM]

I would like to know if anyone has needed to replace fuses in the trailer tow fuse box. According to FCCC there are three boxes on the left front fender. Those three PDM/PDC's are for cab & chassis systems. FCCC says that there is a fourth box that is temporary mounted on a wood board near the batteries when the chassis is shipped to Jayco. What Jayco does with that fuse box is a mystery at this point. The trailer cable from the coach to the trailer was smashed under the trailer landing gear going into a driveway. I have been able to get all trailer lights and brakes back working less the trailer clearance lights. I ran a jumper wire from the license plate light wire on the Seneca to the trailer clearance wire and the lights are working. The problem is on the coach side of the 7 pin plug. Any input would be greatly welcomed.

[Robbbyr]

A Seneca's "trailer" module and fuse location depends on the chassis model. If you have an M2 chassis (up to 2018.5) it is located under the driver's seat. If you have a S2RV chassis it is likely located in the battery compartment. It might be "hidden" up high towards the front of the rig and may be difficult to see.

There was a recent thread on this either here or on Facebook, I will see if I can find a link to that discussion.

[Robbbyr]

See if this thread helps....
https://www.jaycoowners.com/forums/f...ons-71776.html

[SFM]

Robbbyr thanks for the input. I did locate the tow fuse box. I had to remove the coach batteries to get to it. It was stuffed up near the floor and so far towards the compartment door you could not see it from the outside. I found it when I slid out the battery tray then crawled under the coach and looked back up into the corners of the compartment. I relocated the box to a place where it can be accessed without laying in the dirt on the side of the road should another fuse have an issue.

[Rustynuts]

Originally Posted by Robbbyr

A Seneca's "trailer" module and fuse location depends on the chassis model. If you have an M2 chassis (up to 2018.5) it is located under the driver's seat. If you have a S2RV chassis it is likely located in the battery compartment. It might be "hidden" up high towards the front of the rig and may be difficult to see.

There was a recent thread on this either here or on Facebook, I will see if I can find a link to that discussion.

Ahhh but this is where it gets even better....on the first 2018.5 S2RV chassis there is NO added fuse panel or box. I just went round and round with Jayco and Freightliner on this as I was seeing posts of 2019 models having a fuse panel/box mounting up inside the battery compartment. I traced my wiring from the rear of the coach all the way up to the front and could never find it. I contacted Freightliner and they said the first early chassis, one was not specified and didnt have one, all the lighting on the chassis is handled by one of the 3 boxes under the hood, and they sent me all the chassis light related wiring diagrams.....here is what they said.



"The rear lights ( turn, backup and brake lights) are controlled by the chassis module (CHM). The CHM is powered by 3 VBATT fuses. They are labeled CHM VBATT1,2&3. It then will send the power out on those circuits when requested. On your chassis Freightliner did not provide the tow plug harness only a harness for the body side to tie into for the rear lights. I am not sure how the body builder has tied in to our wiring for the tow plug. I have attached the wiring for the rear lamps."


So then to Jayco to see how it was wired, I first requested ALL systems wring diagrams and they sent them all to me. I questioned about the fuse protection of the tow harness and they said it was wired through a Hopkins Pulse Width Modulation Converter and this is the protection between the coach and tow harness, mine is ziptied up under the back by the hitch.


On the 2019 (possibly some 2018.5's) there is a box mounted in the battery compartment and some have said it is mounted up to the top of the compartment and hard to see.

[SFM]

The thread posted is discussing the same problem I had locating trailer fuses. Thanks again. I guess we should just chalk this up to another one of Jayco's poor engineering and wiring problems.

[Robbbyr]

Originally Posted by Rustynuts

Ahhh but this is where it gets even better....on the first 2018.5 S2RV chassis there is NO added fuse panel or box.

I learn something new about Senecas every day!

[Rustynuts]

Originally Posted by Robbbyr

I learn something new about Senecas every day!

I think we ALL do

[TOS]

Correct me if I'm wrong... I have all pins working at the flat plug connection before it goes to the "Pulse Width Modulation Device", but electric is not traveling thru the modulator. So, my problem is not a fuse, but more likely the modulation device, correct?
No problems with my trailer plugs until Camping World did warranty work on my rig (nothing electrical). Guess I'll call them tomorrow w/ questions and hopefully some answers on this problem.