One comment about applying a full 12VDC when pushing down the brake pedal or moving the slide switch. I doubt the brake controller will ever send 12VDC to the trailer brake setup.
The only way I have ever seen a full 12VDC applied to the brakes to draw the 3AMPs per magnet is to pull the brake cable disconnect switch which will apply full 12VDC form your trailer battery directly to brake magnets...
I went round and round with my trailer brakes when I first got my 2010 Ford Truck. First I found out I had no 12VDC feeding my trailer 7-way connector which I finally figured out I was suppose to install a fuse and a relay which was inside my glove box in a plain unmarked zip lock bag. Once I installed this I had 12VDC feeding the trailer when I had my truck ignition key turned on...
Then I hooked up the trailer and went around the block a couple of times setting the OEM truck Brake Controller. This ended up being a 6 on the scale to keep the trailer brakes from from sliding going 30MPH.
The next problem I encountered was I did not seem to have trailer brakes engaged when stopped and holding down my truck brake pedal and I thought this was a real problem as having the trailer brakes locked up sitting at a stop seemed to be important to me. I did several home tests to insure my trailer brakes were working and eventually went to the Ford place with the problem. I was immediately told that the truck electronics has control of the OEM brake controller after 2009 with one being the brake controller disengages the trailer brakes when doing less than 10MPH when pushing down on the truck brake pedal. To override this they told to me use the manual slide brake if I felt like I needed to lock the trailer brakes down at a stop sign. Been doing that ever since...
About the only thing I did not measure was how much DC CURRENT was being used when the Brake PEDAL was pushed in or the manual lever was operated. I read the information about 3AMPS per brake magnet on-line somewhere on how to test your trailer brakes. Most likely from the etrailer.com site.
This was went I found out I needed a clamp-around cable DC CURRENT meter which I brought from AMAZON (Sears Model) and have used it many times measuring DC current associated with my battery banks but never thought to measure the cables when the brakes were being applied after I learned how they worked.
Now I can't find my portable AC/DC 400AMP Current tester anywhere. It is not where it is suppose to be and thats in my Truck Tool Box. I am thinking I left it sitting on a tree stump somewhere camping... geesch... (Another $60 loss haha)
Roy Ken
