2007 Ram Pickup Brakes Lock Up When Gooseneck Cattle Trailer is Connected to 7-Way  

Question:

Expert Reply:

The brakes on your 2007 Ram Pickup should not activate when a trailer is connected. Since your truck's brakes are hydraulic there is no way for an electrically-operated trailer brake controller to interact with the truck's brakes.

If it is the brakes on your trailer that are locking up when connected to the truck, then this could mean that the pin configuration for the trailer connector does not match the wiring on the trailer. It sounds like the auxiliary 12V trailer power and electric trailer brake circuits could be crossed. This would explain why the trailer brakes engage when you plug in the connector: the brakes are then receiving a full 12V power feed that will lock them up.

If you refer to the linked photo you will see the typical wiring configuration for a 7-way blade style vehicle socket. The pin at the 1-o-clock position normally carries 12V power to charge a trailer battery while you're driving; the pin at the 5-o-clock position normally carries the signal from the electric trailer brake controller, from a unit such as the Prodigy P2 # 90885.

It is also possible that corrosion within either the truck socket or trailer plug has caused two circuits to be bridged together. Severe corrosion can actually form a connection between separate circuits. I suggest you carefully inspect both the truck socket and trailer plug for any signs of corrosion. You can use a spray-on contact cleaner (available from a local hardware, automotive or electronics store) and a wire brush like # DW00254 to clean off the contacts.

It is also possible that the trailer was re-wired in a non-standard manner. You can test the trailer plug's functions using a spare battery to check what function activates on the trailer as you apply power to each circuit on the plug.

expert reply by: Adam R

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