4-Way Trailer Connector Does Not Work When Plugged Into 5-Way Trailer Receptacle

Question:

I have seen that you are suppose to be able to just plug a 4 flat trailer into the 5 flat vehicle. I have tried this and the left trailer light just does not work. I have tested my vehicle connector to make sure power is getting thru every slot and I know the trailer lights work because it has been hooked up to other vehicles. Any thoughts?

asked by: Andrew

Expert Reply:

You can plug in most 4-Ways to most 5-Ways but sometimes they are not 100 percent compatible. There can be some design differences and the 2 will not mate up quite right. That could be what you are experiencing. You can also check for any dirt or corrosion in both the trailer and vehicle side connectors.

Besides these issues if there is a weak ground on the trailer it may be that on your vehicle the wiring is not enough to overcome the weak ground and that could be why it works on other vehicles. You will need to make sure the main trailer connector ground and the grounds for all of the lights are attached to clean and corrosion free bare metal surfaces.

expert reply by: Michael H