I have an 05 6.0 with the built in brake controller. I have noticed I have had to slowly increase the gain on some of my trailers over the past year from say a 5 to a 6 or 7 (thought it was just wear on the trailer brakes). I picked up a new Load Max 12T 5th wheel float and was suprised I couldn't get the brakes to lock up. I checked the output at the receiver and was only seeing 3 volts at full gain. I suspect I should be seeing the full 11~12 volts ? Basically the trailer would still creep forward with maximum gain.

Now the trailer brakes do work better when going down the road with the gain set at 9 and seems to work okay. Don't like the idea of running at full gain. On a new trailer I shouldn't be anymore than 5 especially after the brakes have worn in with a dual brake set-up.

Checked the receiver for corrosion, it seems fine. Thinking maybe the brake controller might be going south ? Any suggestions other than buying a new brake controller ? Would like to keep with the factory unit. Any idea what the voltage should be at the receiver with the setting being at 10 (brakes fully on) ?

 

At less than 10 km or so, it won't put full power to prevent locking. Even if you use the manual slider. I think you will find full braking is available at higher speeds then the threshold. This prevents locking tires and it is a biof a frustrating feature as the controller is programmed this way as well as the computer of the truck and the master cyclinder and antilock braking of the truck.

 

Well it makes sense as I definetly have better braking at higher speeds. The trailer weights 8k empty (heavy trailer) so it would take a lot to lock up all 8 tires so maybe a higer gain is needed. My other 7T trailers are lighter and the 4 wheels will lock up at lower speeds when empty. Just hope the MOT/DOT don't have an issue with it if I get pulled over for an inspection and ask to see the tires lock up when I creep ahead. I checked the owners manual it didn't make mention of it (that I could find).

 

The owners manual doesn't describe it but if you use the search function or go into to the top threads there is lots of information. If you use the slider and try and pull away, a tug test, it will show they are working. I never have been asked to demonstrate my brakes on a rptrailer are working, if using as commercial, that may be the case. The other thing to test is the emergency brake. You should be able to pull it and lock them all up. I have had to do this to unload equipment.

 

Here is some good info on how the TBC thinks: http://www.cvsa.org/programs/documen...2001-04-05.pdf

 

Good read thank-you. I would have never figured this out. The Mechanic at the trailer shop did the PDI and was adimate I should be seeing 12V at full gain. Reps, you saved me from installing an aftermarket controller and tearing my truck apart. I'll have to keep a copy of that .pdf file in case I'm pulled over. I'm on this site a lot don't ever remember seeing a post for this with someone having a similar issue.

 

Glad to help! Most people don't pay that close of attention to it. You were pretty sharp to notice the difference. Like you said, I printed a copy of that for my glove box .