4 Pin Connector Incompatibility

[ShortyV8]

I recently purchased a cheap, made in China, single axle utility trailer. The trailer has a similarly cheap flat four pin wiring connector. I assumed all flat four pin connectors were the same but apparently I was wrong. My 2021 1500 Classic has the combination 7 pin / 4 pin connecter but the four pin connecter from the trailer will not fit the four pin receiver on the truck. It seems the pin diameter of the male pins is larger than the female pins on the truck. I ended up buying a 4 pin to 7 pin adapter (also Chinese made) and those 4 pin connectors are compatible which allowed me to use the trailer on the 7 pin connector of the truck. Are there different flat 4 pin connectors or do I potentially have a defective 4 pin connector on the truck?

 

[crash68]

Four pin and five pin flat connectors should all be the same, even able to plug a four into a five.
I would buy a four pin flat pigtail and see if that fits into the truck, if it does replace the connection the trailer using the pigtail assembly.

 

[GTyankee]

I just found out, there is a

4 Wire with 5 pins, the 5th pin would be for back up lights
&
4 wire with 4 pins

wiring always confuses me

 

[04fxdwgi]

I just found out, there is a

4 Wire with 5 pins, the 5th pin would be for back up lights
&
4 wire with 4 pins

wiring always confuses me

The 5th wire, for back up lights, is normally used to release (or block) disc brakes on a surge brake coupler, when reversing. Discs will lock when backing up any upgrade, unlike drums, so the need for a brake line pressure release or brake line block for reverse operation.

See this 5 pin usually on boat trailers with disc brakes. All the ones I owned with discs and OEM wiring had it until I converted to EoH disc and / or converted to 7 pin harness.

 

[csuder99]

Did you buy the truck new ? Maybe a PO has broken the pins off in the connector.