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Working on my '95 Bronco. I have no power at the trailer battery charging pin on the factory installed 7 pin plug. That is the pin that is marked as positive, in the top right corner of the plug. Power is at the maxi fuse under the hood just fine. Wire ohmed out from the trailer plug to the first connection under the rear also. All other pins work as advertised. I compared it to my '01 F150 and find very little differences. Truck must be running to work. This Bronco has never towed anything so I don't know if it is missing a hidden part. It does have the light relay installed under the hood. Is there any plugs along the way from the fuse box to the rear? Any ideas?
Found the problem. On our '95 Bronco, there is another relay box with 4 relays just back of the power distribution box. Number one (towards the fender) is needed to get the power to the trailer battery charge pin in the 7 pin plug. (#2 is still not installed, hmmmm). On our '01 F150, there is only the main power distribution box and this was either included already or is not a seperate relay because power was available with out the towing package being installed.