Trailer wiring need to wire a plug for the trailer. looking for colour codes or diagrams. getting to old to do it with a test light or meter. THANKS!

use the code that came with the plug. Just sort the car wiring with a volt meter or test light.

http://www.narva.com.au/products/browse/wiring-diagrams

use a volt meter to work out which light is connected to which pin on Ford Ranger trailer plug . Hopefully it corresponds to standard trailer wiring diagrams. Test each wire could also use a light bulb with two wires soldered to it or a 12v dc probe.
http://www.amazon.com/6V-12V-24V-Motorcycle-Circuit-Voltage-Electroprobe/dp/B00GYVS0E2
http://www.ebay.com/sch/i.html?_ssc=1&_nkw=Voltage+Detector+Tester+Pen+Non-Contact+Probe+Pen&_sop=7

The trailer connection is usually fed off the wiring from the brake and tail lights If those work, my guess is the wire that goes to ground is open. try following the harness back toward the tail and brake lights looking for broken or corroded connections. If you have a meter or 12v test light try connecting the one end to a good ground if using a meter it should be the black or negative lead. Turn on the running lights and one turn signal while probing the plug if you get voltage or the light to light you have an open ground. Locate and repair the connection.

please dont ask me iam colour blind ,but to overcome this i use a multimeter or a little light and test for current this way ,going by the so called wiring colours is a disaster for me not only the colour thing but the wireing can change colours owing to different suppliers of looms in manufacture ,they run out of one colour and use another ?? you name it i think i have seen it

Forget the fuses to begin with - you need to check each wire with a multimeter with the lights and ignition turned on to see whats happening at the plug end.

No multimeter? then get a 12v test lamp - (check first its working when connected to the battery it works). Now start with say the Tail lights on - connect the single wire from the test lamp to earth (a clean solid metal connection - like towbar) and then press the probe end against each wire in turn until you find the probe light turns or not. If it turns on then mark that wire as Tail - now do the same with the Stop light, then each Right/Left Indicator and then with the Brake light - either have someone press on the foot brake or else jam a suitable sized length of wood between the bottom of the steering wheel and the footbrake to hold it right down. You may also have a Reverse light as well.

You must have ignition ON to check, Stop, Reverse and Turn Indicator lights.
Hopefully this will locate each 'working' wire for you. Then you have to connect these to your trailer plug in the correct position - Google on your area if need be to see what pins are connected to what wires else when you plug the trailer in to the plug it still won't work.
Check out this website for pins and colours - make sure its applicable to your country - http://www.etrailer.com/faq-wiring.aspx as it may differ from country and vehicle..

If you find any wire that does not light up when probed - then check the fuse for that wire's use - ie. Tail etc. If that fuse is ok then check back from the plug to the fuse box as you may have a broken wire or disconnected plug. You will always have an Earth wire - this will not light up when probed - its colour is normally white.

Some people wire trailer plugs differently. If the plug is not wired differently than yours, make sure the tow ball is clean. No rust. That's where the trailer gets its ground from. Usually they will work if thats the case, but not right. I can't remember what the wire colors are right now. Go to etrailer and look up the diagram.

get the standard wiring design
http://www.narva.com.au/products/browse/wiring-diagrams
Yellow is the left turn signal on pin 2
Check trailer plug and see if correct colors used on trailer plug
Would suggest getting a 12volt probe so you can test the car socket when left indicator is going on - flashing
To check that the correct pin has 12volts flashing left on it.

7way- black is 12volt (power), brown, running lights, yellow is left turn signal and stop light, green is right turn signal and stop light, white is ground, blue is brakes, and orange is aux power (can be back up lights, if trailer equipped w/ them). 6way is the same, minus orange wire. I have run into some variations to the above color codes (brown, yellow and green only-sometimes these 3 are different than stated, but only mixed as that group, as to what they control- example would be green is running lights, brown and yellow are turn signal and stop lights, the others should be as stated), if you have any trouble with things not working properly, it may be due to these variations, although the above are pretty standard. If you have an ohm meter you can check as you go (check for power at black wire- should be constant 12v, turn on turn signal and check for power-it will fluctuate from approx. 12 volts to 0 volts as the signal power pulses in the wire) hit the brakes, blue wire should show power, etc. Let me know if you need more help as you go.

I'm assuming you have a trailer towing package.
Below is the wiring diagram. It appears the dark blue is your stop lamp wire you may be looking for.
Let me know if anything is different.
Regards,

I believe you can look up the manufacturer of the trailer plug kit and find the wiring diagram there. On alot of the trailer plug kits, they have pics and diagrams in the package. The 7 pin plug (truck side) is available with the pig tail set up that plugs directly into the wiring harness for the lights. Then all you would have to worry about is the 2 wires for the electric brakes.