Disc Brake Controller

[EPaulikonis]

I had a recent incident that has me slightly confused and concerned. I went to storage to do some work on the Savannah. I didn't plug it into shore power, but I did go in and turn both battery circuits to the on position in the front compartment. I opened the dining room slide with no issue. When I started to open the main kitchen slide I heard a weird noise. Slide stopped moving, but the sound remained. I went to the front compartment and found that the hydraulic brake controller was the culprit.

I couldn't figure out how to make it stop, so I started removing wire nuts until I found the hot wire for the controller. In hind sight, I guess it would have made more sense to just turn off the batteries. Either way, I got it to stop.

I plugged the rig into shore power (30Amp). I then went back to the front compartment and reconnected the wire I'd disconnected earlier. No more noise and all slides operated fine.

I do not use a battery tender when in storage and it was not plugged in all winter either. The batteries were checked and topped off with distilled water prior to storage and were turned off in the front compartment all winter.

So the question is, why did the brake controller actuate under battery power after the slide stopped moving? Is it possibly because the batteries were not fully charged after being in storage all winter? Does the brake controller draw power from both the TV and battery when in tow? Just trying to understand what caused the brakes to engage, or at least the hydraulic motor to engage, when on 12V battery power source.

Before you ask....I didn't have my multi-meter with me to check the batteries at the time so I don't know charge state. Go figure!

 

[SNOKING]

Re: ATF: Landmark - Brake Controller

Do you have a propane sniffer that is still powered with the battery switches off? Chris

 

[EPaulikonis]

Re: ATF: Landmark - Brake Controller

I don't believe so. Never heard any beeps or chirps from a CO2 monitor or like in the coach over the 2-years I've owned it. I'd really have to go through and check with shore and battery power disconnected to say for sure. I haven't noticed any direct wiring to the batteries that circumvent the cutoff switches. Another question for the factory I guess; are there components direct wired to 12V battery source that do not turn off when cutoff switches are turned to the off position?

Do you have a propane sniffer that is still powered with the battery switches off? Chris

 

[jbeletti]

Re: ATF: Landmark - Brake Controller

Eric - per codes, both the brakes and the propane detector are wired before the battery cut-off switch. That said, I can't think of why your brakes would have been actuated unless you pulled the break-away pin or had something connected up to the 7-wire plug.

 

[cookie]

Re: ATF: Landmark - Brake Controller

I'm guessing that you have electric/hydraulic disk brakes so the noise you hear is from the hydraulic brake actuator. Brake controller is in your truck.
I don't have an answer for you on the noise but two things come to mind.
Did the breakaway switch get activated? Someone pull the cable?
Also I believe that the brake system should be continuously powered. It should not deactivate when the battery cutoff switch is off.

Peace
Dave

 

[SNOKING]

Re: ATF: Landmark - Brake Controller

The brake actuator may have a low voltage sensor that causes it to activate? At any rate it appears to batteries were down on charge! Chris

 

[EPaulikonis]

Re: ATF: Landmark - Brake Controller

So that's two that confirmed brakes are powered outside of cutoff switch to batteries. Also see that the propane sniffer is drawing continuous power in same manner.

I can assure you, the break away pin was installed properly and not pulled. The hydraulic brake actuator turned on by itself when the slide stopped moving due to insufficient power. Again, I only had battery power because I didn't do a walk around to insure shore power was plugged in, so there was no 120V source when this happened.

I'm trying to figure out why the power fluctuation caused the hydraulic brake actuator to turn on. The break away switch is electrical, not mechanical...true? If so, could drained batteries (<50%) cause hydraulic brake actuator to engage in similar manner as break away switch being pulled out?

 

[cookie]

Re: ATF: Landmark - Brake Controller

The breakaway switch is a simple on/off switch. No power will pass unless the pin is pulled.
The actuator should only get power from two sources, your truck or the breakaway switch.
You might consider calling the actuator manufacturer for some insight.

Peace
Dave

 

[jbeletti]

Re: ATF: Landmark - Brake Controller

Eric - I agree with Dave, time to call Dexter (if Heartland installed the brakes) or Carlisle (if MORryde installed the brakes).

 

[Titanguy]

Re: ATF: Landmark - Brake Controller

Agree, contact the mfg. Sounds like a wiring problem. Might get a wiring diagram and check to see that the cold side of the breakaway switch is wired properly.

 

[SNOKING]

Re: ATF: Landmark - Brake Controller

Like I pointed out above the actuator may have a circuit that monitors it's 12V source, which is the trailer battery/batteries(which are charged by the converter or TV, and if voltage gets low it tries to stop you to check things out). Or it glitched on low voltage input, and fired off the pump. If the manual does not talk about low voltage monitoring then it most likely was a glitch. Chris

 

[EPaulikonis]

Re: ATF: Landmark - Brake Controller

I have a call in to Dexter's Hydraulic Brake Actuator expert (Sam). I'll follow up with any info he shares.

 

[EPaulikonis]

Re: ATF: Landmark - Brake Controller

Sam confirmed that a weak, poorly charged, battery will confuse the circuit board resulting in a fault state. The hydraulic brake actuator senses a drop in power and the fault at the circuit board may cause power to be applied to the brakes. Sam did say that removing all power from the circuit board is the only way to clear the fault and return the system to normal operation, which is exactly what occurred when I disconnected the hot wire nut lead to the actuator assembly. So now I know.

I have a call in to Dexter's Hydraulic Brake Actuator expert (Sam). I'll follow up with any info he shares.

 

[danemayer]

Re: ATF: Landmark - Brake Controller

It sounds like your brake pump actuator gets power from the RV batteries all the time (if the cutoffs are ON), and not just when the emergency breakaway switch is activated or when the truck is connected. So if you're parked at a seasonal site for 3 months, the pump actuator is powered the whole time. I suppose if it's in a standby mode, maybe that's ok.

 

[SNOKING]

Re: ATF: Landmark - Brake Controller

Which raises a bit of a the question of trailer brakes with a failed shorted out trailer battery, as power to run the pump is dependent of the trailer battery. The brake lead just tells the actuator how much it should brake. The power to do that comes from the trailer battery and its charging circuit from the TV. Seems good fresh trailer batteries are a requirement for such systems, as the charging circuit to the trailer would never overcome a failing battery.

Chris

 

[ksucats]

Re: ATF: Landmark - Brake Controller

I'm sorry but something just doesn't sound right - assuming I'm reading this correctly. If the battery(ies) voltage drops then the hydraulic pump will kick off. So, now you're heading down the highway and suddenly the actuator kicks off, develops 1600 psi and locks all four wheels. How is that safe! More importantly, is that really possible. I have limited electrical knowledge but if the voltage is down, will the actuator run well enough to develop that pressure. A rhetorical question I know but we had an incident with our past trailer.

Seems that there was a gasket between the brake fluid reservoir and the circuit board panel. On ours, fluid leaked and, while getting onto I-70 and at approximately 50 mph, all four brakes locked up. Ruined four Goodyear G614s real fast and left me locked up in the middle of the on-ramp. I had to put the truck in 4-wheel drive and was able to pull the trailer to the side. Called Good Sam's and 35 minutes later a mobile tech arrived. I was heading back home, san's brakes (luckily a very short drive). We ended up cutting the wires to the actuator - the entire time I was stuck there the brake controller kept running. The following day we had a Mobile tech come out. He looked at everything, didn't see any problem. Actuator hooked back up and worked just fine. We went to Branson several weeks later without incident. HOWEVER, at 4 AM one morning we got woken up by the most raucous sound going. The brake controller had kicked off all by itself. I took the ole wire cutters and cut two power leads - one from the battery and another that was labeled to be from the truck (the truck was not connected but I cut that wire anyway.) Long story short, we had to replace the actuator because fluid had leaked out onto the controller board. The actuator was made by a company that is no longer in business as the kit was installed in 2006.

 

[Titanguy]

Re: ATF: Landmark - Brake Controller

I know little about the way the Dexter pump is/should be wired but it uses a 4 wire system and seems to be wired into the breakaway switch and house battery. Titan does not do this. We use a 5 wire system to isolate the breakaway switch and house battery. When unplugged from the truck, the breakaway switch when pulled will still operate the actuator. When the truck is plugged in the breakaway switch and house battery are on a separate circuit so when the truck dis-connects the breakaway is pulled activating the actuator using the house battery.

In normal operation a signal to stop is sent thru the blue wire directly to the actuator to start the pump. The 12v power wire takes over and provides maximum voltage directly from the truck. The house battery and breakaway is not involved.

In November Dexter bought Titan brake systems. Since then Dexter has examined the circuitry in the Titan Actuator and is making some changes to the circuitry in the Dexter Actuator to more resemble the Titan.

 

[SNOKING]

Re: ATF: Landmark - Brake Controller

Dexter manual. Chris
http://www.pjtrailers.com/Files/Support/Dexter_Elec_Hyd.pdf

 

[EPaulikonis]

Re: ATF: Landmark - Brake Controller

Thanks for the manual Chris. Titanguy is spot on...Dexter is a 4-wire system. Guess the link to the house batteries (no separate break away battery that I'm aware of) is the important piece for failure I experienced due to low battery power and no shore or TV power connections at the time.



I'm no electrical genius, but I'm guessing there was a power drop when the slide stopped. When I removed my finger from the slide button, battery power came back and was sufficient for hydraulic brake actuator to sense this as a broken circuit like the break away switch had been activated and it caused a fault and applied battery power to the assembly. The batteries were low, not completely dead, so the voltage came back strong enough when I stopped pushing the slide switch to actuate the pump.

I would expect low power on the battery, or a break in the electrical connection to the battery, while connected to the TV isn't an issue since vehicle would continue providing steady state power to the hydraulic brake actuator assembly. Probably wouldn't notice a trailer brake malfunction until the trailer is de-coupled from the TV and the break away switch is pulled that is. If there's little/no battery power from the rig's battery(ies) (or the separately installed break away battery), the trailer would keep rolling even though the break away switch was pulled since there's no power source to turn on the hydraulic brake actuator assembly.

Hopeful I'm wrong. If this is how it works, the system has some serious safety flaws.

Dexter manual. Chris
http://www.pjtrailers.com/Files/Support/Dexter_Elec_Hyd.pdf

 

[danemayer]

Re: ATF: Landmark - Brake Controller

If there's little/no battery power from the rig's battery(ies) (or the separately installed break away battery), the trailer would keep rolling even though the break away switch was pulled since there's no power source to turn on the hydraulic brake actuator assembly.

Hopeful I'm wrong. If this is how it works, the system has some serious safety flaws.

Whether electric drum brakes, or electric/hydraulic disc brakes, the emergency break-away function depends on trailer battery power.