Point Five Ambo Build

[zuke]

Also on your tail lights. Maybe I am missing something but doesn't the standard 7 pin from a ford run the indicators separate to brake lights.

Nope, The 7 Pin connector doesn't have a separate wire for the brake lights, since in a two wire system it's the same filament in the bulb. It has a right and a left turn indicator wire, and it uses these same wires for the brake lights, but doesn't pulse the signal through the flasher relay.

 

[patoz]

Mate I suggest you just get a set of Little Giant steps and rework them to suit. They are a little spendy but nothing compared to trying to make your own. The best part is that the handle folds down and they are just 3 steps. Mine mount inside the door and I just put them out when needed. Missus thinks they are about the best modification we have made.

Link to steps

Bevan, I believe you have solved the step problem in one move! :clapping::beer:

It looks like the 2-Step model floor to 2nd step measurement is 17-3/4", according to one Amazon reviewer, which should be just about right for my rig. Plus, these steps look like they would be just about right to reach a bag awning mounted on the side or just above the rain gutter, which is something I would not be able to do with a mounted set.

I do like the idea of self supporting steps though, in case of mud or uneven ground. But, the 2-Step model is less than a hundred bucks on Amazon, so I can live with that.

Also on your tail lights. Maybe I am missing something but doesn't the standard 7 pin from a ford run the indicators separate to brake lights. The conversion for all the trailers I have had over here is done at the tow vehicle. And is just for the 4 pin setup. So why don't you just run a new 7 core straight to the back of the rig and wire it in. Preferable with a descent double insulated cable instead of the flat ribbon and corrugated tube that most trailers have. Like this stuff.

Nope, The 7 Pin connector doesn't have a separate wire for the brake lights, since in a two wire system it's the same filament in the bulb. It has a right and a left turn indicator wire, and it uses these same wires for the brake lights, but doesn't pulse the signal through the flasher relay.

John is correct about the brake and turn being combined on my truck. Here is what I have...

This is a photo of the connector on my truck, which has since been replaced with a new but exactly the same piece.

I ran into this a few years ago mounting trailer lights on a temporary bumper, due to the OEM refrigerated box being removed. The issue stemmed from vehicle wiring that did not match up with the wiring in the trailer lights.

The Upgraded Heavy Duty Modulite Circuit Protected Vehicle Wiring Harness # 119190KIT may solve your problem.

Check out https://www.etrailer.com/p-119190KIT.html

This kit uses a powered converter with circuit protection to safeguard your vehicle and the module. It also includes everything necessary to hardwire it to your vehicle. Be sure to use the included tester to make sure you have the correct wires before splicing. The colors on the trailer harness are as follows below.

Green = right turn
Brown = tail lights
Red = brake light
Yellow = left turn
White = ground
Black = 12 volt battery lead

DzlToy, I'll study that converter tomorrow when I can call them and ask questions if I need to.



I think what I may do is build a small mock-up out of plywood and 2x4's so I can mount all of the lights in their respective locations and wire them up for testing by actually plugging them into my truck, before mounting anything on the ambulance module itself.

Thanks guys for all the help...

 

[patoz]

You know, sometimes you just have to sit down and have a drink to clear your mind to see the obvious!




I now believe I know why the turn signals would not work when I tried to test them, by applying power directly to the leads at the tongue. The turn signals are controlled by relays mounted in the electrical panel in the module, and the relays require 12VDC power to operate. When I conducted these test, there were no batteries connected to the electrical panel, so the relays did not work.

Maybe there is hope after all! :wings:

 

[zuke]

Hahaa, Been there, Done that

 

[rlrenz]

Wheeled Coach may have used relays to control the turn signals in order to also use them as part of the warning light system. As already mentioned, you can do the job with diodes if you want to simplify things to just turn signals.

If your load is low enough, there's Amazon's 5 amp, 100 volt Schottky diodes - $3.86 for 10: https://www.amazon.com/gp/product/B00HGALQLY/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

If the load could be higher, there's Amazon's 10 amp, 50 volt rated Schottky diodes - $3.86 for 10 of them the last time I looked (https://www.amazon.com/gp/product/B00HGALQLY/ref=oh_aui_search_detailpage?ie=UTF8&psc=1)

 

[patoz]

Thanks Bob,

I'll keep that in mind, but I may have to get you to draw me a schematic since I'm a little rusty when it comes to that.

 

[rlrenz]

D.O.A. is a similar setup, the brake lights still run from the original wiring, While the turn signals were separate and run through the module cabinet.

I think I'd just go with a whole new harness for the tail lights, and if you can locate the clearance light wiring, reuse that and tie it into a new harness.. Your truck is a two wire system though, and .5 is going to be a three wire system. So I think you're going to have to treat it as if you were towing another vehicle, (Tow Bar setup) which is going to require some diodes;

Pat - this diagram should do the job - but we can get down to the details when you're ready for them.

The diodes only allow current to flow in one direction. Considering the price of the diodes, I'd use the 10 amp diodes. Shottky diodes have minimal voltage drop - they are standard for solar applications.

 

[zuke]

Pat - this diagram should do the job - but we can get down to the details when you're ready for them.

The diodes only allow current to flow in one direction. Considering the price of the diodes, I'd use the 10 amp diodes. Shottky diodes have minimal voltage drop - they are standard for solar applications.

One other thing that's key to this whole thing, You can't use the existing RV plug on the the Ford, you'll need to go further back in the vehicle wiring harness to find a point where the signals for Brake and Turn signal are already separated. You can use the electric brake signal from the RV connector for the brake lights, but you'll have to go all the way to the flasher relay to get a separated turn signal (One good place for this might be the Ford's FRONT turn signals.)

Doing all this means a non standard connection, which will make .5 harder to put behind another vehicle too as far a hookup and go scenario.

 

[patoz]

Thanks guys!

I'm working on something else right now, so I'll have to get back to this.

 

[rlrenz]

The easiest solution is to wire the body like a trailer. Ignore or eliminate the old vehicle wiring, and start from scratch.

 

[patoz]

The easiest solution is to wire the body like a trailer. Ignore or eliminate the old vehicle wiring, and start from scratch.

That is exactly what I have in mind.

And somewhere I have seen a ready made adapter to convert from a 2 wire to a 3 wire system when doing this, I just can't remember where.

 

[patoz]

I found it!!



Commonly used for vehicles being towed by RVs, campers and rental moving trucks. Converts 2-wire systems on the tow vehicle to 3-wire system on vehicle being towed.

CURT 56196 Converter

 

[zuke]

Awesome! Definitely looks like it's gonna do what you need.

 

[patoz]

Awesome! Definitely looks like it's gonna do what you need.

I haven't had time to study all of them yet, but they have some other models that even have the 20' wiring harness already attached. Of course, I would go through my 7-pin connector though, so I could use the 12V+ lead for a trickle charge to the house batteries or to the battery backup for the electric brakes.

http://www.curtmfg.com/Category/193/Taillight Converters

 

[zuke]

Looking at the ones on the Web-Site, It looks like the first one you saw is the best for your application, there have to be some fairly complex electronics in there, as it's got to be detecting square wave form leading and trailing edges to know the difference between a turn signal and a tap of the brakes. Honestly, I really wouldn't have believed such a device existed if you hadn't found it!