Hi All, and Thanks in advance. I bought a used 2012, E350, 5.4 Liter, and need to install 4 wires for a Trailer. L/Turn/brake, R/Turn/brake, Park lamps, & ground.

The Problem is that the Ford Trailer wiring plug has no power to it.
I tested with both a meter and a 12 Volt trouble light.

Do I have the correct Ford Trailer plug?? The Ford Plug was on top of the L/ frame rail near the spare tire, with part # PA/SPS - GF 20 on it, with slots for up to 16 wires, Mine only has 4 wires, Green, Yellow, White, and PINK.

Green for R/turn/Stop (I saw this list of wire function on this forum.)
Yellow for L/turn/Stop
White for Ground
Pink ???? (Is this the new "brown" for parking lights???)

The under hood fuse box has good fuses and the relays in slot 37 & 38 click when the turn signals are turn on.

What should I check? Any advise is welcome.

Thanks Kenny Lyon

 

I believe that Ford didn't put in the relays for powering the RV wires if it didn't come with the trailer tow package. I'd be checking with the local Ford Parts dept.

 

Do you have power on fuse 48 in the underhood fuse box?

 

Hi Franklin2

With the ignition key on or off, there is power at fuse 48, for the Trailer Tow Stop/Turn Signal, under the hood. Used a 12 volt test light to test for power and to test the 20 amp fuse. Fuse is good.

Thanks for your suggestion, I had not tested for power there.
Any other suggestions?

Thanks Kenny Lyon

 

That fuse feeds the trailer turn relays. Check for power at the relays next. The green and yellow wires you mentioned in your post that run the rear come right out of these relays. The hot wire that feeds the relays from fuse 48 is a violet/red wire to both relays.

 

Hi Franklin2
Both relays have power to one of the four socket pins for the relay. The pin with power is on the front/right side. Both relays "click" when the Van turn signal are used. With the relay out of the socket, the Van turn lights still work.

These two relays are installed with the notch, in the top of the relay, the notch is on the right side. The relay in socket 39 for the back up lamps is installed with the notch on the left side. (Each relay has Ford on the top, standing in front of the Van looking in at the Fuse box, you can read the Ford on relays 37, & 38. Relay 39 the Ford name faces the rear of the Van.)

Could the two relays be installed 180 degrees out? If the relays were installed backward, could the relays, now be damaged?

Thanks Kenny

 

Hi Franklin2
As I do not have 12 V power for the trailer parking lamps at the rear of the van. I used your idea, & I jumped ahead to checked for power at the relay socket for the Relay in slot 6, for the Trailer tow/Park Lamps. 12 volt power is present when the Van parking lights are "on". The power is on the rear/right pin in the relay socket.

Thanks Kenny Lyon

 

Hi Franklin2

Also With the 37 & 38 relays, out of the socket, and the van turn signals "on", I get a pulsed 12 volts on the relay pin at the left front side of each relay socket.

The pin with solid power is on the front/right side.
The pin with pulsed power is on the left/front side.

Thanks Kenny Lyon

 

Since the relays are clicking, we can assume they are installed correctly. The van turnsignals make the relays click, and when they click they are turning the #48 fuse power on and off. So #48 is really driving the trailer lights, not the van's turnsignal circuit fuse.

See if you can figure out the relays some more. I am not sure what Ford relay you have, and if it's a bosch type relay. Here's a picture of a bosch type relay.



If you could figure out what "87" and "30" are on your relay, you could make a little jumper and jump these two spots in the relay socket, and then you should have power all the time on the rear wires.

 

Hi Franklin2
Again thanks for your help.

The #6 relay is a four pin, Bosch type, Part #9C27-14B192-AA, and is marked for the connectors # 85,86,87, & 30.

The other two relays,37 & 38 are not Bosch type, and the 4 connectors are not marked. Part # 5L3T-AA 0831D52.

Your idea of a jumper wire on the relay socket, 87 & 30, would not allow the trailer turn lights to flash, but would be a way to check the wiring with out the relay.

You stated that these relay go directly to the Trailer wires at the back of the Van. Power is getting to the relay, if the relay is good, then the wire to the back of the van is disconnected somewhere.

Can you post or e-mail a wiring diagram of the Van wiring?
The repair manual at the auto part store does not show the Trailer wiring.
Thanks Kenny Lyon
kenylyon@hotmail.com

 

Hi Franklin2

Relays 37 & 38
The pin with solid power is on the front/right side.
The pin with pulsed power is on the left/front side.
The other two pins would be for relay Ground and for the van Trailer turn/stop wire.

How would I know which pin to place the jumper on? Placing +12 Volts on the Ground would be a new problem.
It is my quess that the somewhere between the relay and the rear of the van the trailer wiring is disconnected. Thanks for your help. Kenny

 

You are on the right track. All the relay does is put the solid 12v power pin onto the pin that goes to the rear. Take your meter and put it on ohms, and then probe the remaining pins, the one that is ground should give you a very very low reading. You can probe the other pins to make sure, but the ground pin should give the lowest reading on ohms resistance scale.

If you get it figured out and feel confident, you can then jump the pins and see if you have solid power to the rear(you are correct, this is just for testing). If you still don't have power, you know you have a problem with those two wires going to the rear.

 

Hi Franklin2
On the bench I test the relays for the correct connections.
Relay 5L3T-AA is a small square box with a connection pin in each corner.
The relay top has a notch in it. The relay can be installed with the notch to the left or to the right side of the vehicle. The connections inside the relay are made across the box shape. Turning the relay box 180 degrees gives you the same connections, and relay function.

Both of my relays are good.

The wire to the rear of the van does not have power. Must be disconnected somewhere.

I need a wiring diagram for 2012 E350.
Thanks again. Kenny Lyon
kenylyon@hotmail.com

 

This is all I have.

 

Thanks Franklin2 for the wiring diagram. Looks like a connector marked C110, now to find it on the van. Kenny Lyon