Caravan tow bar electrics

provided that the caravan is not over 3 tons and is fitted with electric brakes there will not be a problem
there is a load limit on the tow ball of around 150 kgs but if you use stabilizer bars ( which you should be using) , that makes it legal as the lift provided when you adjust the bars takes the load off the ball and makes the van more stable on the road
there will be a decal on one of the front door openings with the max towing load allowed

possible that the trailer plug is not wire correctly

it is also possible that the trailer has bulbs and the kia uses led units which will throw out the electronics
you may have to talk with an accredited auto electrician as there may need be an adaptor or blub change in the trailer electrics

Underneath the stick, there might be a problem like a stuckup or broken plastic shifting bearing. Check this one.

Ues a test pen to trace the wire see where the short is most common bad ground

How did you check it? Look at it? I think it's a sealed bearing. While driving, slowly sway the car left to right and back again. Does the noise become more prominent in either direction? When you put mor weight on a bad bearing they make more noise. Turning left puts more weight on the right side and vice versa.

You need to swap wires on pins 5+6.

Saves having to use a supplementary socket
01 Yellow Left Indicator
02 Blue Fog light
03 White Earth (35amp)
04 Green Right Indicator
05 Brown Right Side Light
06 Red Brake Lights
07 Black Left Side Light
08 Yellow Reversing Light
09 Green Permanent live
10 Blue Ignition live
11 Red Earth (35amp)
12 Black Coupled Trailers
13 White Earth (35 amp)

you need new signal switch assembly. unfortunately federal laws do not allow john q public to remove the steering wheels as the airbag has to be removed. Take it to the dealership or a reputable repair shop.

if you toggle the switch and they work then your problem could be the switch

hi! first check the plug on the van,the socket on the car, then the little blue push connectors the fitters use,last but not least the lamp tabs on the lamp holder!