Dead Jack

[JimW]

i’ve been putting this question off for too long now, so here goes. A while back, I took the trailer in for a brake job. The trailer sat for a few days after repairs were made, so when I finally went to hook up, the batteries were dead. I connected the Bargman 7pin up to the truck and found the jack did not work. All the lights were working, the brakes worked great, signals worked, but not the jack. I also learned that the batteries did not charge while being towed. That jack worked just fine when plugged into the 30 amp post, fortunately. The truck is a 2019 Silverado that only had 14,400 miles on it at the time.

My questions are: Should the jack have worked even though the trailer batteries were nearly dead. Second, if so, should there be current at the white or black pin of the Bargman, and how to test that. One of my earlier Silverados needed a fuse installed if towing, could that be the case here? Jim

[n2916s]

Sounds like the 12VDC charging line in the 7way is not working. Your Silverado may not have come with the fuse inserted in the correct slot.

[CBWELL]

The jack is "usually" hooked direct to the batteries. If the batteries were dead or almost dead, ther would not be enough 'Juice" to use the jack. It draws quite a load. You would not get enough charge into your batteries from just being connected to the truck. Get a test light and see if there is power to the charging terminal on your 7 pin connector.

[JimW]

Originally Posted by JimW

i’ve been putting this question off for too long now, so here goes. A while back, I took the trailer in for a brake job. The trailer sat for a few days after repairs were made, so when I finally went to hook up, the batteries were dead. I connected the Bargman 7pin up to the truck and found the jack did not work. All the lights were working, the brakes worked great, signals worked, but not the jack. I also learned that the batteries did not charge while being towed. That jack worked just fine when plugged into the 30 amp post, fortunately. The truck is a 2019 Silverado that only had 14,400 miles on it at the time.



My questions are: Should the jack have worked even though the trailer batteries were nearly dead. Second, if so, should there be current at the white or black pin of the Bargman, and how to test that. One of my earlier Silverados needed a fuse installed if towing, could that be the case here? Jim

UPDATE

As it turned out, the AC to trailer circuit fuse (slot #2) was burned out and has been burned out since soon after purchasing the truck. I do have an idea what caused the fuse to blow. What I learned definitively is that the jack does work robustly even when both batteries are dead. Hooray! I was surprised to learn that that circuit must aid trailer braking as I had to decrease the Gain by almost half, 10 down to 5.5. I bought an extra fuse and a fuse puller that I’m carrying at all times.

[turk123]

Good news you found the problem. In a similar event, now that I've added lithium batteries to the Airstream, I needed to disconnect the 7 pin from charging the batteries when hooked up. Imagine my surprise that my 2017 F-250 not only did not have the fuse in that position but did not have the relay either. All this time I'm being careful to disconnect after travel, and the batteries were not even hooked to my trailer's charging circuit!