joshbuys Posted September 30, 2010 Share Posted September 30, 2010 Complaint: Trailer brakes don't work when stepping on the pedal. Gain is set at 10. Trailer brakes work if manually pressing Brake controller switch. Truck was in my dealership a while back, another tech looked at it and verified everything with the trailer brakes is operating correctly. Customer says the trailer is equipped with "electric" brakes. I'm thinking maybe it's actually equipped with "electric over hydraulic brakes", but haven't been able to look at the trailer yet - I went on a drive with the customer this morning, but they could not leave the truck/trailer as they are taking the trailer to the RV dealer to have some other stuff repaired on it. Any thoughts would be appreciated. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted September 30, 2010 Share Posted September 30, 2010 Use the trailer brake emulator and verify that the output signal is at the trailer connector. If the led ramps up and lights brightly then the truck syustem is working properly. Advise the customer that the trailer brake control system will only work with trailers that are equipped with electric-actuated brakes. Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted October 1, 2010 Share Posted October 1, 2010 What Keith said is mostly correct, but it looks like Keith was flat rate reading. If the trailer brakes work when the controller is pressed, it doesn't have hydraulic surge brakes. If the cust complaint is correct your problem is in the controller. However, I'll tell you a few things about trailers- "surge brakes" (hydraulic) are relatively unusual these days and most trailers have electric brakes. As far as "electric over hydraulic brakes", I think someone is confusing them with surge brakes, which use no electricity and have a MC built into the trailer tongue. Regarding electric brakes, 99-100% of them are wired with Scotch Locks from the factory and commonly have "issues" within minutes or miles. I own 3 trailers right now in addition to several others I have owned in the past, and I've had 3 trailers custom built in the last few years. I've never been able to find a quality harness in a trailer so on the second day of owning a brand new custom trailer, I gut the harness and start from scratch with quality stuff so it will last. Tell your cust that even if the truck IS healthy his trailer is likely not, and to have someone pick up all the wheels and verify all brakes are working when the controller is activated. I've seen trailers not even make it home from the trailer shop (new) with harness and Scotch Lock problems. If you don't have an emulator try a headlight bulb or something that draws 5-10 amps wired into the plug. Good Luck! Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted October 1, 2010 Share Posted October 1, 2010 Assuming this is TBC, are there any codes in the TBC module or the SJB? If the trailer brakes work with the hand control, we can safely assume that the wiring from the module to the trailer plug is OK and we should be able to infer that F5 in the BJB is OK. If the trailer has electric over hydraulic brakes ( not hydraulic surge brakes ) then I do not think that the TBC controller will activate them <noway - nohow>. (I've been wrong before but TBC output is TBC output... no matter what commands it). Other questions that go begging... Was the system factory or dealer installed (does it have the correct master cylinder? Is the ICM configured for TBC? I would think it is if you can read the TBC gain). I heartily recommend reading "Diagnosis And Testing" in section 206-10 of the WSM. There are several pertinent messages that may or may not be displayed in the message centre - seeing them or not seeing them may help determine your course of action. If you can, the WBT course will offer some insight into the system. FWIW, I really, really, really recommend checking out the 2011 TBC system.... Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted October 1, 2010 Share Posted October 1, 2010 What Keith said is mostly correct, but it looks like Keith was flat rate reading. Guilty. Quote Link to comment Share on other sites More sharing options...
joshbuys Posted October 1, 2010 Author Share Posted October 1, 2010 In doing some research online, I've learned that to get electric over hydraulic trailer brakes to work with the 2010 and older TBC modules, you would have to wire 2 brake magnets into the circuit in order to give the TBC module the electronic feedback it is looking for. I knew there was an answer out there somewhere, as I worked with a guy several years ago that dealt with this on another customers truck, and had come up with a way to fix it. It's nice that ford has made the 2011 trucks TBC modules compatible with both electric and electric over hydraulic brake systems. Thanks for all your input! Quote Link to comment Share on other sites More sharing options...
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