Hello, my E550 van front/box back has an electrical problem.

Sometimes when I first start it and step on the brake my backup beeper warning goes on. Most times it stops once I start driving, but sometimes it continues for a while or comebacks back by chance. Doesn't matter where the shifter lever is, park, reverse or drive.

Yesterday it woke up really bad and anytime I used a turn signal or flasher I got a fast blinker and beeper going. Figured I had a light bulb out. Looked around the truck and noticed no taillights. Shut truck off went inside a building with flashers on, beeper was going. When I restarted, beeper stopped and I had right side taillights but no left Drivers side.

Drove back home still no left side.

Have no idea where to start looking. Electrical is not my strong suit.

Any and all help appreciated.

 

You didn't say what year, but it may not matter, it sounds like a grounding problem. Pull the lights and see if you can find where the ground wire bolts to the body back there.

 

Sorry you are correct should have said what year. It is a 2003 E550.

Bodied by Morgan.

 

I looked in the factory diagrams, and they do not have anything on the rear lights on a E550. That's when it dawned on me that your vehicle was probably a stripped chassis from the factory, the lights will be inside the aftermarket van body or whatever it is. So I can't really help as far as locating the grounds, but the way it's acting, I am thinking that is your problem. If you can't find the grounds, just add new ones. Look up front and make sure there is a good ground to the frame from the battery, and then go to the rear and tie a new ground to the frame and then to the body and or the light housings.

 

Hi Franklin, thanks for the help. As far as I know you are correct, it was sent to Morgan trucks as a van front and bare rear chassis.

Haven't done much electrical so forgive me if I sound…well stupid.

So all I have to do to set new grounds is just bolt wire from the frame to the body, frame to the lighting? Am I splicing into the ground wire in the lights? If so what gauge wire should I use? I will match the battery gauge for the battery, but not sure of the rest.

My interior box light also does not work. Have not had the time to see if its the switch, light housing, or wiring up to it. Replaced bulb still doesn't work.

What part of the world might you live in? Was hoping maybe you are local to Nj and persuade to look at it? Had to try.

Thanks again.

 

Sorry forgot to mention, this truck has two batteries. Has a 7.3 turbo diesel in it.

Not really sure how they work together? Are they wired together as one large one? Will check both grounds.

Since this all seems to originate when I step on the brake pedal, where would the brake pedal electrical ground be? Into the harness or stop somewhere near pedal?

Also wondering if you know much about the van body portion on these trucks? I have a leak in the cowl drainage area that finds its way into the drivers side firewall/floorboard interior. Think I have it pinpointed to where the water would drain out, it disappears into the fender area that I can't get to. Have the cowl cover out, the inner fender out and there is a bracket welded to a panel that hides everything.

Thanks

 

Why don't you pull both rear lights apart, and scratch your head a little bit on how they grounded the lighting. You should have a hot wire for the running light, a hot wire for the brake/turn, and probably another hot wire for the back-up light. That means 3 hot wires and 1 ground. If you can't find a ground wire, they might be grounding the light with one of the mounting bolts or studs going into the light housing.

Try to figure this out. If you find the ground wire or the stud is bolted right there to the body(is this body metal or fiberglass?) then I would start suspecting the whole body has come ungrounded from the truck. If it is a metal body, you might just have to simply get a short piece of 10 or 12 gauge wire, bolt one end to the truck frame and bolt the other to the metal of the body. If you just want to experiment and see if grounding really is the problem, you can get a long scrap piece of wire, hook one end to one of the battery negative terminals, and then lay the wire on the ground and take the other end and stick it on a clean metal place on the body or one of the ground wires to the lights(if there are any) and see if that straightens all your problems out.

The two batteries are tied together as one. So you can use either one for grounding.

The brake pedal doesn't have a ground. This is how it works; Power originates from the battery and then the fuse box, and runs up to the brake pedal switch. When you press the pedal, power runs out of the switch on another wire, goes through the turnsignal switch, and then runs out of the cab, down the frame and up into the cargo box somewhere. It then runs to the light bulb in the rear. It goes through the light bulb, and then it needs to get back to the battery negative to complete the circuit. This is where they use the "ground". The hook everything to the metal frame, and use it like a big wire to run everything back to the negative of the battery to complete the circuit.

It sounds like you have a bad ground, so when you hit the brake and the power goes back to the light, goes through the bulb, it then has no place to go. It's mission is to find the negative of the battery, so it will go backwards up through other circuits(like the reverse beeper) to find a place to get back to the battery negative. That's why when crazy things seem to happen, it's usually a grounding problem.

 

Wish someone had explained it to me like that years ago. Thank you very much.

 

Thanks you for all your help.

Found a very loose ground strap right off of my second battery and someone didnt' know how to use crimps on my taillight. Only one wire was actually attached. Went to look at ground and everything fell apart.

Have another question for you. I have to put a couple of exterior lights on the outside of the box, probably on the passenger side of truck. Would use it when we setup my equipment. Would like to use the lights you might see on a firetruck or ambulance. Flat spot lights.
Question is where is the best place to pull power from? Would like to have a separate switch or two (one in cab, one in box). I would also like to wire some other accessories in the future. Just not really would where I should tie into on this truck. Is there a block that is set up for this or should I tap off of the second battery? Never had a vehicle with two batts.

Thanks again.

 

I don't know when they started it, but Ford started putting what they call "upfitter switches" inside the cab on some models. That would be a good place to get your power for the lights.

If you do not have upfitter switches, I would go ahead and add another small aux fuse box right off one of the batteries.

Figure out what wattage lights you are looking at. Take the watts number, divide it by 12v, and that will give you your amps. You can buy small fuse boxes in the store, or you can buy small separate circuit breakers that can be mounted under the hood near the battery. Just try to keep the fuse box or the circuit breakers near the battery +, since the wire going from the + post on the battery to the circuit breakers or fuse box or boxes will be unprotected.

Then run out of the circuit breaker or fuse box with the appropriate sized wire. I usually run #10 for a 30-40amp circuit, #12 for a 20 amp circuit and #14 for a 15 amp circuit. These are much larger wires than the factory uses, but it eliminates any voltage drop and will make sure your lights are nice and bright.

Run the wires into the cab to a switch for any lights you want to control there, and run wires to the cargo box to switches you want to control there. If you want to control the lights from either place, you will have to use a two position switch with 3 terminals, known as a single pole double throw switch. You will have to use two, one in the cab and one in the cargo box, and run two wires between the switches as "travelers", much like a 3 way switch in a house stairway.

 

Thank you once again. Great info. Wish all forums got the results I got here.

You have any experience with water leaks? Same truck, I have a leak in the driverside cowl area that is leaking into the firewall/dash area. Have it pinpointed down to where it drains, but can't access it from the underside.

Thanks.

 

I don't know about the vans, but the trucks in the early 2000's had a terrible time with windshield leaks. The water would leak down the inside of the firewall, and get the fuse box and the GEM module wet. That causes all kinds of electrical problems with all the automated stuff like electric windows, interior lights, etc.

 

Hi Dave,

Ground issue is good now, went ahead and tried to fix my brake/tail lite problem.
Tailight assembly was falling apart and someone didn't use a crimp terminal properly.
So I went out and bought led taillights both upper and lower now.

Installed the left side no problems and kept the right side intact just so I didn't have multiple things apart. Once I knew the left side was good took apart the right. Noticed that right passenger side wires where different colors then the left drivers side.
-Drivers side was green backup/ whites turn signal/blk taillights. All work good.

- pass has red and brown and green.
When I cut the sheathing back to get more wire to tie into there was an orange wire broken off about an inch into the sheathing. It was not attached. Not sure what that does?
Attached all the reds to reds and new lites blacks to truck browns, left green off until I get a backup lights. Lights only came on when headlights are on. No turns/ haz/or brake lites.
I also noticed that my ABS dash lite is on now.

Do you know the wiring diagram for my taillights? Not sure what I am doing wrong and what I should do with the orange wire?

Thanks,
Jim

 

Your wiring is from the body manufacturer, so any Ford references I have are not going to match.

I do know LED lighting can cause problems sometimes. It doesn't present enough load to the system and can cause things not to work right. They do make load resistors that you can add to load the circuit down and still use the LED lights.

 

Yeah ford dealerships won't help. Morgan body is not getting back to me either. so frustrating. Just want this done.

Am probably going to have to install the resistor as I see the left side blinking really fast.

Well thanks for your help anyway. Appreciate it.

Jim