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Chris (aka-Moose)
Chris (aka-Moose), RV Mechanic
Category: RV
Satisfied Customers: 48704
Experience:  16 years of experience
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Question for an auto/RV mechanic. We have been experiencing

Customer Question

Question for an auto/RV mechanic. We have been experiencing a brake problem where the trailer brakes go full-on for one second. It has occurred intermittently a total of 6 times in two years. I have all the data to support the problem description.
Submitted: 1 year ago.
Category: RV
Customer: replied 1 year ago.
Problem StatementIntermittently, the brakes of our fifth wheel trailer lock up for less than one second, while being towed by our Chevy truck.Incident DetailsOver the last 2 years, we have experienced 6 incidents of the trailer brakes locking up, each for less than one second. Each incident is during “tow mode”, where our truck is hitched to our fifth wheel. The following are observations during these incidents:1. All incidents occurred during highway speed while pulling the trailer
2. The trailer experiences brief lock-up of trailer brakes
3. We are in “tow mode”
4. A few of the incidents occurred while cruise control was active; most of the incidents did not have cruise control active.
5. The speed is reduced due trailer brake activation.
6. The incident takes less than one second.
7. The vehicle RPMs do not go up.
8. The truck brake light and ABS light both go on.
9. We always pull over to the shoulder after the incident.
10. Brake light and ABS light stay on until the engine is turned off, restarted, and vehicle brought to at least idling speed.Our truck and trailerChevy Silverado 3500HD LTZ, crew cab, long-bed, dually truck. We have no performance enhancing computer chips or devices. Stock.Redwood 38BR fifth wheel (41 feet)What we have done so far1. We have taken the Chevy truck to different dealers a total of four times. Each time the dealer checks the EBCM and determines any codes. Nothing has been found wrong the Chevy truck by any of the dealers. Codes have been documented.
2. For example, in the last incident, the EBCM threw a “U0100” code. According to, “The generic OBD trouble code U0100 is a serious situation where the signals between the electronic control module (ECM) or the powertrain control module (PCM) and a particular module have been lost. There could also be a problem with the CAN bus wiring disrupting communications.”
3. We have had our trailer in for service a couple of times, with nothing found so far.
4. I have talked with the manufacturer of the trailer brake actuator (Cargo Towing Systems).
5. I have talked with the manufacturer of the trailer (Crossroads).
6. I have had many conversations with Chevy mechanics.
7. I have de-activated my truck air springs, to be sure that there are no current spikes being given to the EBCM due to this aftermarket device. The problem has re-occurred after the air springs were de-activated.
8. I have had my truck external fuel tank wiring checked by the Chevy dealer to be sure it is wired properly.
9. I have purchased a new CAM MOD device to support the trailer brake actuator, according to Cargo Towing Solutions.
10. I have replaced the 7-pin connector that goes between the truck and trailer, including the plug-in receptacle that mounts to the truck bed.
11. I am ready to have the trailer gone over top to bottom to see if there are any potential intermittent shorts (not an easy task).SummaryI’m looking for what specifically to do to solve this problem, before someone gets hurt.
Expert:  Chris (aka-Moose) replied 1 year ago.

Welcome, I'm Chris (aka Moose) I prefer to work when others don't, I am here around lunch and after dinner till after midnight.

What year is your truck?

I get the feeling you have not touched the brake when this occurs, correct?

Do you ever get these warning lights when not towing?

Customer: replied 1 year ago.
Hi Chris. The truck is 2013. The incidents occur without touching brakes. The warning lights only happen during the incidents.
Expert:  Chris (aka-Moose) replied 1 year ago.

Was the diag for this U code done and were any repairs for it done?

Customer: replied 1 year ago.
No action was taken based on U code. The mechanic checked EBCM and said it was working ok. He suggested there might be some problem in the RV generating a signal. No idea how to proceed or what the problem is that is causing the incidents.
Expert:  Chris (aka-Moose) replied 1 year ago.

For the trailer to be to blame. The trailer would need to have a wire shirt and back feed power to the tuck on the electric brake wire or the right or left stop turn lamp circuits. Since you said this occurs with the brakes not used that means the left and right stop turn relays are open and the electric brake feed only goes to the brake control. Neither of which could cause the truck to receive a brake signal input and trick the EBCM. I can not see the trailer to blame for this case. I think its the EBCM to blame in this case and its telling the brake controller the brakes have been applied thus the controller applying the brakes. My suggestion is to start off with a new EBCM on the truck. If this occurred more often i would say to hook RV to another truck but 6 times in 2 years, that is going to be impossible to duplicate.

This is my 1st answer, but does not have to be my only answer. You the website and myself expect you to have a ~~~5 STAR EXCELLENT~~~ experience with my help. Please let me know if you are pleased by selecting a star rating above or by replying and saying your pleased. Not rating or rating 1-2 stars does not benefit you nor me in any way. Follow up and reply as often and when needed, there is no extra charge to do so.

Thanks Moose.

Customer: replied 1 year ago.
Hi Chris. I'm off on a day hike and will study your suggestion when I get back.
Expert:  Chris (aka-Moose) replied 1 year ago.

No problem, camping and hiking myself in TN.

Customer: replied 1 year ago.
I appreciate your replies. However, I have learned that the source of the problem is the RV manufacturer installed the wrong Controller Adapter Module with my Hydrastatic Brake Actuator. I have arranged to get the new part. The EBCM on my vehicle has been checked and re-checked by the Chevy dealer and has been ruled out as the problem. At this point, I'd like to close out the Just Answer process. I can't say that your replies were instrumental, as it did not resolve my issue. But that is not your fault. How should I proceed?
Expert:  Chris (aka-Moose) replied 1 year ago.

Use the contact us link at the bottom to close the post.