Power Problems at 7 Pin Connector

spydorman · 08-23-2020, 07:23 AM

Hi, Having some trouble with the signals getting to the 7 pin connector. Not exactly sure what went wrong. It was working fine hooked up to my Jeep Wrangler in the past and now all I can get is running lights to work. No turn or brake lights. Noticed it when I got to a campsite and thought it might be a problem with the 7 pin to 6 pin round cord between the coach and the Jeep. All the lights still work on the rear of the Coach.
Took the connectors apart on the cord and found a couple of wires where the clamp screws had loosened and one that had completely fallen out. Thought that was the problem, tightened everything up replaced the screw, but I still have the problem.

Used a Multi-Tester at the 7 pin Socket on the coach with the key in the On position and the only voltage reading I get is at the Power location and the Running Light location. Can't get any reading at the Right turn/Brake Light or Left Turn/Brake Light Locations.

Took the 7 pin apart and again only getting readings at the Running Lights and Power Positions. Same thing at each individual wire going into the back of the connector.

Had me wondering if the loose wire in the cord might have shorted and blew a fuse.

Tried to find a fuse somewhere that might have blown, but couldn't find any bad ones.

Started stripping off some of the Corrugated Plastic covering from the wire harness to find the connections between the Ford Chassis at the rear and the wiring harness that Winnebago adds on. All the connections look good there. Looks like there are a set of wires that power the rear Coach lights and another set of wires that power the 7 pin. Checked for power in the wires on the Ford side of the harness and the only hot RH and LH Turn/Brake wires that showed a voltage were the ones going to the Coach Lights. The ones going to the 7 Pin were dead. There are 10 wires going to the rear of the Coach at that junction. They were labeled as follows:

Blue - Electric Brake Power
Green w/Orange Stripe - L.H. Turn W/Brake
Black w/Purple Stripe - Back Up Light
Brown - Park Lamps
Orange w/Blue Stripe - R.H. Turn w/ Brake
Bright Green - Brake Lamp

Green - Trailer R.H. Turn/Stop Lamp
Brown w/White Stripe - Trailer Park Lamps
Black w/Green Stripe - Trailer Back Up Lamp
Yellow - Trailer L.H. Turn/Stop Lamp

There are also four other wires in this harness near the connection that turn back and I assume go to the other side of the Coach. They are labeled:

Green w/ White Stripe - L.H. Turn Only
Blue w/White Stripe - R.H. Turn Only
White - Trailer Ground
Black w/Blue Stripe Interior Lamp

See the pic below for this connection location.

200822-Hitch Wiring 2.pdf

200822-Hitch Wiring.pdf

So anyways, after a frustrating day of trying to find the problem, I've turned here hoping for some help. Is there a fuse location that I do not know about? This is a 2016 model 35G on a 2015 Ford F53 Chassis. Found the fuse panels at the base of the bed, the one under the dash to the left of the emergency brake, the one in the center top of the engine compartment and the one in the small storage locker just behind the front right wheel. Checked all the fuses in these locations. Is there a relay that might have gone bad and if so, how do I test or find out which one might be bad?

Thanks for any help.

Morich · 08-23-2020, 09:14 AM

Looks like you've given it some thought and about all the info we should need, so let's give it a go!
First let me do some checking as I sometimes have a bit of brainfreeze and find it pays to check.
When checking these I don't think of it as having separate fuses, etc for the trailer hitch wiring but just those being tied to the coach wiring at the rear. When checking for voltage on the turn signals and stop lights, we have to have those powered by having the signal on or somebody stepping on the brake. Did you maybe skip that ?
I might go this way to check and retrace myself as I think it may have you jumping at ghosts which are not really a real problem.
With the tow vehicle disconnected, do the turn signals work as normal from the front seat? Leave them working/flashing one way and go to the back to check if there is intermittent power flashing at the correct post on the trailer connection.
Basic idea is that if the coach is working for turn and stop, the connection should also see this flashing power.
So first I try to sort if it is a problem in the RV or in the tow or connections. I would want to test the coach working, then is so, connection working okay and add the tow connection and vehicle last as I check each point along the way.
See how that goes and let us know and we can go more if needed and try to find a cool shady spot! HAH!

spydorman · 08-23-2020, 09:58 AM

Quote:

Originally Posted by Morich

Looks like you've given it some thought and about all the info we should need, so let's give it a go!
First let me do some checking as I sometimes have a bit of brainfreeze and find it pays to check.
When checking these I don't think of it as having separate fuses, etc for the trailer hitch wiring but just those being tied to the coach wiring at the rear. When checking for voltage on the turn signals and stop lights, we have to have those powered by having the signal on or somebody stepping on the brake. Did you maybe skip that ?
I might go this way to check and retrace myself as I think it may have you jumping at ghosts which are not really a real problem.
With the tow vehicle disconnected, do the turn signals work as normal from the front seat? Leave them working/flashing one way and go to the back to check if there is intermittent power flashing at the correct post on the trailer connection.
Basic idea is that if the coach is working for turn and stop, the connection should also see this flashing power.
So first I try to sort if it is a problem in the RV or in the tow or connections. I would want to test the coach working, then is so, connection working okay and add the tow connection and vehicle last as I check each point along the way.
See how that goes and let us know and we can go more if needed and try to find a cool shady spot! HAH!

Hi, thanks for the comeback.

With the tow vehicle detached:
I did have the key on and had the LH and RH signals turned on. Went back and checked after doing so and the lights on the coach work, but there was no signal in the 7 pin socket or the wires leading to it. Had my wife step on the brake and again the coach works fine, but no signal to the 7 pin.

There is definitely a whole different set of wires in the wire harness that Ford supplies that feed the 7 pin versus the lights on the rear of the coach. See the photos I attached of that area. The turn brake wires intended for the Coach have voltage in them when the signals are on. The wires for the 7 pin do not.

Morich · 08-23-2020, 10:51 AM

That's where the brain freeze question comes back to bit me! Looks like you have the right story and there are some relays on that year and model. But the problem then becomes that it is considered Ford wiring and Winnebago does not post any of the chassis parts online, leaving us to hunt and peck for Ford info which is closely guarded secrets.
A search for info led me to get some vague ideas that do show tow relays but little help on finding them. I did get this one picture from a source which appears to possibly sell the info. So it might or might not be worth anything but I thought I might throw it in and let you look for a relay IF the picture might look like anything you've found. My Ford has the relays in a box with fuses and the names of the relays are in the box lid. Maybe get lucky to find that and spot a bad relay?
Stretching but about all I see for any help at all:

spydorman · 08-23-2020, 11:08 AM

Thanks. I think the panel shown is the one just left of the emergency brake. I think Winnebago changed the layout somewhat. Havent fooled around with relays before. Is there a way to determine if their bad just by looking at them or do you have to test each one?

BobC · 08-23-2020, 11:46 AM

Have you checked the individual wires independent of the connector?

spydorman · 08-23-2020, 12:10 PM

I took the back half of the socket off and checked the terminals there and then checked each wire individually where they come into the back of the connector.
Took it another step and stripped the plastic conduit off the wire harness back to the point where the Winnebago harness joins the Ford harness and checked the wires there. Again no voltage readings.

BobC · 08-23-2020, 12:37 PM

Quote:

Originally Posted by spydorman

I took the back half of the socket off and checked the terminals there and then checked each wire individually where they come into the back of the connector.
Took it another step and stripped the plastic conduit off the wire harness back to the point where the Winnebago harness joins the Ford harness and checked the wires there. Again no voltage readings.

Too bad, a bad socket would have been an easy fix.

Morich · 08-23-2020, 02:20 PM

Sounds like you have the metering part down okay, so checking relays is lots easier to do as it is more a continuity check than anything. IF you can find the correct one, it "might" be a simple plugin type and it might also have the diagram printed on the side. Hoping there but do find it on my Focus relays.
I would expect to find a simple drawing of a pair of lugs connected to the coil shown as a coil maybe. Testing the coil for continuity is a matter of testing one lug to the other and getting some kind of resistance.
Straight battery and ground to these lugs should make it jump so you can feel or hear it move to close contacts that should be shown on the drawing, too. No guess if it will be one that has on direction only (single throw?) or two ways to move (double throw?) but you want to see no continuity change to full, low resistance continuity when operated.
In other words, open close and pass or not pass current.
We're getting pretty far into guessing and hoping but maybe some diagram like this???

spydorman · 08-23-2020, 04:13 PM

Ok, Finally solved. Went back under the drivers side of the dash to look at the relays there. I swear they think everyone's a contortionist. At 67 hardly even flexible anymore.

While I was under there, I decided to try testing the fuses one more time. I had forgotten that all you need to do is push the pointed probes from the Multi-tester into the small holes in the top of each fuse to check continuity. And much to my surprise I came across a 20 amp fuse that I couldn't zero out. Pulled the fuse and found it had blown. Location didn't jive with what I had seen in the manual for the trailer turn signals, but hoped it was the one. Put a replacement in and wallah! Turn signals and brake lights now work! Put everything back together, brought the Jeep up behind it and plugged it in and all the lights work on the rear of the Jeep! I took a picture of the fuse panel and pointed out which fuse it was in case this thread might help someone else. It is attached below.

Thanks to Richard and Bob for trying to help me with this. Much appreciated. Guess we all learned something. When I started in on this, I really didn't think they would have a whole separate circuit for the trailer lights with their own fuses either. But they do!

200823-35G Fuse Panel with Trailer Fuse shown.pdf

imnprsd · 08-30-2020, 08:10 PM

Good job staying with it!

I'm not sure where you found your tow light fuse. Can you elaborate if it was in your main circuit panel or was there a separate fuse box at the rear of your RV?

I see you have a gas-RV so I'm not sure where they would put it?

Note: Your multi-tester is good for a lot of things, but did you also use a circuit tester like this one below to diagnose your tail light problem?

This is the best way to probe for any 12v circuit and you can find it at Walmart for $10-$12.

spydorman · 08-30-2020, 08:20 PM

Hi, The fuse panel that it was in is below the dash, just left of the emergency brake. I had attached a picture. Hopefully it came through..
I did use one of those testers. Really helped out a lot!

Goodspike · 08-30-2020, 08:30 PM

I haven't been following this thread, but assuming those items circled in post 4 are fuses, I find that fuse design to be difficult to tell if they are blown. IMHO you need to use a continuity tester on them.

Oh, and FWIW, my Chevy PU has separate fuses for each pin (except the ground).