Truck/trailer wiring issue.Very frustrated !

[BudsRam]

Hey All,
Background:
Rewired a trailer for a 4 pin harness... replacing the old original harness that was way past needing switched out.
My problem is that only the left turn signal is operational. Thought maybe I had an issue on the truck side so checked fuses and chased wires and couldn't find any cut, frayed wires or anything that looked like it was damaged or causing problems.
I never was comfortable with the electric side of any vehicle but I don't know what to do next. Any help with this BS is greatly appreciated!

Thanks in advance

 

[SniperDroid]

Go to a big Uhaul dealer and buy a five dollar trailer wiring tester. It's a plug with led lights on it. That will tell you if the truck connector is good. Go from there.

 

[JayLeonard]

Go to a big Uhaul dealer and buy a five dollar trailer wiring tester. It's a plug with led lights on it. That will tell you if the truck connector is good. Go from there.

Tractor Supply also has those.

 

[Dan J]

Check trailer light grounds

 

[Ramtor]

Hey All,
Background:
Rewired a trailer for a 4 pin harness... replacing the old original harness that was way past needing switched out.
My problem is that only the left turn signal is operational. Thought maybe I had an issue on the truck side so checked fuses and chased wires and couldn't find any cut, frayed wires or anything that looked like it was damaged or causing problems.
I never was comfortable with the electric side of any vehicle but I don't know what to do next. Any help with this BS is greatly appreciated!

Thanks in advance

Did you program the trailer lights to work? i used alphaobd…

 

[Daily Driver44]

so if you rewired the trailer then you know which wires are which,
the cheap way out without buying any tools that you may only use once is to just use some scrap wire and back probe the wires in the plug and attach to a 12volt battery.
if its a turn signal bulb it doesn't have to blink in order to be tested.

if the trailer all checks out then move to the towing vehicle.
as previously stated and depending on the vehicle, some trucks need to be programed for the trailer hookup. i really don't understand why the factory does that to a truck but there it is.

Hope this helps!

 

[tron67j]

The above is good advice, has the trailer worked correctly? Hook up to someone's truck and just verify all works.

Meanwhile, you can do the cheap test above. Get a ground wire attached to a good point of the truck then insert a wire into each pin of the truck plug, connect the wires to a bulb and turn on blinkers and see if the bulb lights up. That will test both your ground and individual power wires at the same time for free.

Good luck.

 

[RamDiver]

The OP posted and disappeared on 11 April.

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