Tow Power Controller Fix

[SteveG]

It’s raining off and on here in Tallahassee today so I have a little time to post.

When we tried to depart on this Thanksgiving trip not a light would come on the Toad. I had to dig deep into the bowls of our 2004 Journey 36G to find a thing called a Tow Power Controller (TPC). It's a box sized about 5" x 5" and a device designed and provided by Freightliner that Winnebago locates in a number of different locations apparently depending on model and year. It has 7 fuses and 8 relays. Freightliner, thru the help desk, can provide wiring schematics.

As I understand it, this device provides the interface signals between the MH and Toad so there is no direct electrical connections thus isolating the MH and Toad electrical systems. The TPC is buried behind a compartment panel in the power compartment and it was not an obvious find. The Allison ECM is also located there below the TPC. I had to call both Winnebago and Freightliner to get enough location clues. But once there I found three open 20 amp fuses. That explained the no lights part but not what caused them to open. That mystery might still be open. I installed new fuses and all seems to be illuminating and blinking normally. Although I think I may have found the problem as the umbilical cord clamp located at the toad end plug was loose.

I will insert a photo of TPC box location and appearance next week after returning home. SteveG

[SteveG]

It’s raining off and on here in Tallahassee today so I have a little time to post.

When we tried to depart on this Thanksgiving trip not a light would come on the Toad. I had to dig deep into the bowls of our 2004 Journey 36G to find a thing called a Tow Power Controller (TPC). It's a box sized about 5" x 5" and a device designed and provided by Freightliner that Winnebago locates in a number of different locations apparently depending on model and year. It has 7 fuses and 8 relays. Freightliner, thru the help desk, can provide wiring schematics.

As I understand it, this device provides the interface signals between the MH and Toad so there is no direct electrical connections thus isolating the MH and Toad electrical systems. The TPC is buried behind a compartment panel in the power compartment and it was not an obvious find. The Allison ECM is also located there below the TPC. I had to call both Winnebago and Freightliner to get enough location clues. But once there I found three open 20 amp fuses. That explained the no lights part but not what caused them to open. That mystery might still be open. I installed new fuses and all seems to be illuminating and blinking normally. Although I think I may have found the problem as the umbilical cord clamp located at the toad end plug was loose.

I will insert a photo of TPC box location and appearance next week after returning home. SteveG

[SteveG]

The three following photos are from our 2004 Journey 36G so the locations may differ with other models. The general location is in what I call the power compartment.

First photo shows the power compartment. The Tow Controller is located behind the sheet metal wall to the right of the photo, adjacent to the transfer switch box which in this photo has the top removed. The wall can be dismounted by removing screws; they are obvious.



The second photo shows the Tow Controller with cap removed mounted above the Allison ECU which is the silver color.



The third photo shows a closer look of the Tow Controller. The TC has the cap off and you can see the six 20 amp and one 10 amp mini fuses mounted in a row across the bottom. There is one slot for a spare fuse which I found empty. The eight gray boxes are control relays. The cable plugged into the top left goes to the toad plug mounted at the fender. The FreightLiner help desk can provide wiring diagrams. Before I put this back together I removed the strain from the two wiring cables feeding into the top of the Tow Controller.



Although this photo does not show the third box clearly, it is mounted below the Allison ECU and is called, per FreightLiner, a Vehicle Interface Module (VIM). This contains no fuses just relays. The relays: neutral start relay, exhaust brake relay, neutral sense relay, reverse lamps and two spares.