Brake Madness

[vangoes]

Let me start by saying "electric brakes can drive you mad"! With that out of the way, my primary problem is low voltage at the brakes when hooked to truck. Now here is my confusion. Voltage at truck plug without trailer hooked is 12.4v. Hooked to trailer, the voltage at the junction box in the kingpin is only 7v but if I disconnect the blue wire feed to the trailer brakes the voltage returns to 12.4v. With this low voltage trying to diagnose the individual brake magnets is virtually impossible so I decided to unhook truck and try the breakaway switch route. Now, the voltage at the junction box is higher than the previous 7v but is still only 10.4 volts. If I again unhook the feed to the brakes, the voltage in the junction box jumps to 12.6v, and is the same voltage at the battery. To sum it up, there is voltage drop when ever the brakes are inline.

I decided to test each brake using the 10.4 volts that the breakaway was providing. Here are the results: Voltage 9.2 - 9.6v; Amps 2.3 - 2.5; resistance 3.4 - 3.5 with magnets disconnected and 1.1 - 1.2 with magnets connected. I believe the results are normal and expected considering the low 10.4v to start with. There is no one brake giving results outside the ranges of the others which tells me the magnets are all good.

I also believe the truck controller is good as is provides 12.4v when the trailer is unhooked.

If anyone out there has any suggestions to help me find the problem I would greatly appreciate it.

 

[cookie]

Van, what problems are you having with the brakes? Not stopping?
At the junction box, the blue wire from the umbilical wire nuts to another blue wire that is encased in a grey coated cable.
That wire is 12 gauge. Somewhere in the belly of the trailer that #12 wire sizes down to #18.
I believe what you are experiencing is plain old fashioned voltage loss.
I would upgrade the wiring to #12 wire all the way to the magnet wires.

Peace
Dave

 

[JanAndBill]

Check all your ground connections including your plug.Dirt and corrosion will prevent a full voltage.

 

[vangoes]

Thanks Cookie,
I've been thinking that a connection/wire gauge in the belly going to the breaks is suspect but what confuses me most is the difference in the drop with truck voltage versus the drop with voltage from the breakaway (battery) voltage, I'm leaning towards a weak ground somewhere.....thinking about adding additional grounds in the line. What do you think?

 

[Jim.Allison]

Im concerned about your BATT voltage being at 12.4v to start off with. Your BATT should be reading in the neighborhood of 13.5v. A 12.4v BATT reading (either house BATT or motor BATT) is 50% discharged at 12.4 volts.

Disconnect your batts, check them and charge them, get autozone to load test them. Clean all connections from batt to trailer. Get some current back there to your plug. Then do your testing.

 

[cookie]

Van, if you change out the wire to # 12 you will erase the doubt of grounding.
If you do have a bad ground somewhere you could see the voltage drop because of it.

Peace
Dave

 

[JanAndBill]

A previous poster brought up a good point on battery voltage. Are you testing your voltage with the truck running or off??? Two batteries in the truck or one??? First off you need to be sure of your power source, a 12 volt automotive battery (at rest, truck off) is presumed fully charged at 12.6 volts (6 cells at 2.1 volts each). Each battery should be tested individually (disconnected from others)

If the battery is

12.5 = 85% charged
12.4 = 65%
12.3 = 50%
12.2 = 35%
12.1 = drained

If your truck is running you should be reading 13 volts or better. You indicated your voltage was 12.4, which would mean a less than fully charged battery, if this is an at rest voltage. However voltage alone is not an indicator but a symptom. You need to load test each battery, individually (disconnected) from any other. A bad cell will cause significant voltage drop under any load. You also indicated you use the break away switch. When you did this did you have the power cord disconnected?? If you did then you also need to check the coach battery, for voltage and load.

If each of your batteries checks out then you either have a short somewhere in the circuit, a bad magnet, or loss of ground. Disconnect your brake wire at the king pin box and each of the brake magnets. Using an ohm meter connect to one end of the brake wire coming from the junction box and one end to the trailer frame. If you read any resistance, you've got a short. Check each of your ground connections for corrosion. You don't say what size brakes these are, but a 10-12" brake magnet normal resistance should be in the 3.2-3.5 Ohms range. When checking the amperage draw you should use a separate (known good) battery, with the trailer disconnected from the vehicle. Here is a good link to walk you through the testing process:http://www.etrailer.com/question-10824.html

Again, you can't just test one part of the system and assume other parts are okay.

 

[vangoes]

Dave,
My initial problem is unacceptably weak braking ability. My initial thought was grease but thought I would check everything electrically before pulling the wheels. That when I discovered the extremely low voltage. As far as my wire gauge, it is #12 all the way to the left brakes, however, the wire from the left side brakes through the axle is #18 (why Dexter does that???). There is a slight voltage drop from the left side to the right side but not significant. I plan on changing this but need to find root cause first. thanks.

 

[cookie]

I think there may be some confusion here.
Van, what wire are you checking for voltage? Are you looking at the 12 volt supply or the blue wire for the brakes?
If it is the wire that supplies current to the trailer we are talking one thing.
If you are looking at the blue brake wire that will be something else. You will not see the full 13 or so volts at the blue wire in a static state.
That is unless you are jumping the plug wire from 12 volt to the blue brake wire.
Remember, you have a proportional brake controller that determines how much current to send to the magnets.

Peace
Dave

 

[vangoes]

Bill and Jim, to clear up my initial post, my voltage at the truck plug with trailer disconnected is the 12.4 volts (truck running, contoller set at 10). The voltage at the battery in the trailer at rest, truck disconnected is 12.6. Resistance at the magnets (disconnected) is 3.5 and resistance in pin junction box (magnets connected is 1.3). BTW, my truck contoller is a 2013 Dodge (factory controller). The brakes on the trailer were equally as bad with my "08 Ford.

 

[Bob&Patty]

Van, if you only have 12.4 volts with the truck running, you should have at least 13+ volts. You have an issue somewhere in the truck. You need to check the voltage/amp inputs to the batteries from the alt/gen. You might have one battery that has a bad cell. That one battery could take down the whole system. I would check all the battery terminals for corrosion and the grounds to the eng/frame from the batteries. Most trailer harness's in the truck have a redundant ground somewhere close to the rear of the frame.

10 seems to be awful high. My '13 GMC is set at 2.5 and with the brakes adjusted well on the Horn...it stops just fine.

 

[JanAndBill]

A proportional brake controller applies voltage based on the deceleration it senses. A truck at rest will not have the same voltage reading, even when you apply manual. I believe that 10 is the minimum default power setting from the factory.

You need to check your batteries at the source, disconnected and hooked up. 12.6 volts is a full charge on an at rest battery (without any parasitic drain). Hooked up if your batteries are not reading 13 volts or better with the truck running you either have a bad alternator or bad battery. Be aware that a battery can be reading nearly normal on voltage and still have a bad cell, which is why you need to load test each one.

As to the brakes on the trailer any checks regarding amp draws should be done with fresh battery connected direct to the brake magnet, not through the wiring and definitely not hooked up to the truck. Go to the link I posted earlier, it has a simple instructions for testing.

That said, you mentioned you had the same problems with a previous truck. The newer model Dexter's have self adjusting brakes, the older ones did not. By chance have you jacked up a wheel and adjusted the brakes? Even self adjusters some times get out of adjustment.

 

[mobilcastle]

Grease on the brake shoes seems to be a regular occurance. After you do the wiring pull the hubs. What amps are you getting at each brake

 

[5erWonk]

Van, I am having a similar problem but it was only noticed when I had my suspension replaced, before that my braking was fine. The confusing part for me is the 3V drop from the truck plug to the J-box but only 1.0V from the box to the brakes.

 

[vangoes]

Has anyone with a 2012/2013 Dodge tested the brake voltage coming from the truck with trailer hooked up, full brake applied and setting on 10 and not moving. As stated in OP, my voltage at the jbox under this condition is very low. I've sent Dodge a question about the contoller (proportional/delayed???) and what would the expected voltage be under these condtions but I have not received an answer.

 

[JanAndBill]

Has anyone with a 2012/2013 Dodge tested the brake voltage coming from the truck with trailer hooked up, full brake applied and setting on 10 and not moving. As stated in OP, my voltage at the jbox under this condition is very low. I've sent Dodge a question about the contoller (proportional/delayed???) and what would the expected voltage be under these condtions but I have not received an answer.

The voltage coming off the controller could very well be only 10. On automatic using the foot pedal, the voltage is regulated based on deceleration and pressure on the pedal and is "ramped" up depending on what you have the controller set.

Using the manual slide function, the voltage will also vary depending on how far you move the slide and your controller settings for percentage of power and ramp up. You can adjust the voltage at the controller as a percent of available vehicle power and the ramp time in seconds, on both automatic and the manual slide function. You want to be careful though as running either up to much could result in a trailer wheel lockup on heavy braking.

 

[JanAndBill]

Van, I am having a similar problem but it was only noticed when I had my suspension replaced, before that my braking was fine. The confusing part for me is the 3V drop from the truck plug to the J-box but only 1.0V from the box to the brakes.

Just curious have you tried cleaning the pins and the sockets on your plug? Also, if you have the split pins, in the socket, try spreading them just a bit so they make a better contact. I had a lot of problems with this on our 5th wheel, until I finally installed a plug under the top rail, in the bed of the truck.

 

[Jim.Allison]

Soooooooo you think the trailer brakes are equally as bad as with a previous truck with a different controller? Have you got the EVIC set up for this trailer. I set up my EVIC. My fiver is trailer #1, it is set to heavy trailer. Then I run at 6 to 6.5. When you say bad are you saying by voltage measurements or by braking ability/performance. Your trouble seems to be mysterious which leads me to believe that your settings (in the EVIC) for the RAM brake controller need to be looked at (as others have suggested for an inertial controller) I selected heavy for no other reason than my trailer is near capacity of the truck. I say mysterious in that it is consistent across two vehicles. Perhaps voltages are not your problem but rather your performance either perceived or actual.

If your concerns are performance related, the question is; when did you begin having performance issues or have you always had performance issues? And then what do you consider performance issues?

I do not know what is good performance or bad performance is with electric brakes on a vehicle this size. I have tried everything to determine what setting to use and can only tell the difference in setting the gain at 0 then gradually moving up until I get breaking that I think is good. It might be poor as heck, but I don't have the experience to know better. But I do know that I had an occasion to brake at 100% from 65 MPH. My whole fandangled rig came to a fully controlled stop in record time.

Did I understand that you serviced the fivers brakes once? I noticed that Dexter provided "Never-Adjust", which theoretically needs no adjusting (we will see), if you did service the brakes did you change anything except the friction pads?

Like a previous commenter on this post, I do not like the simple wiring that I see, not so much the gage but just the exposure and the possibility of bad contacts and broken wires, bug me. This is acceptable in the trailer industry, Heartland has just followed suit, not being critical of them. But still the connections behind the tire don't instill confidence.

I have the same truck as you do, I cannot get a grip on what is good braking. I use the techniques that I have read about and those on youtube videos to set the gain and cannot get anything but a powerful tug at 20 mph, which to me indicate they are working but this technique does not help me determine the gain setting. I run at least 6. One source says to run at 10 if you have trouble determining a gain setting. I have done this and it seems to work but causes me concern that my trailer is doing all the breaking, but I have no evidence that it is doing all the braking.

If this post does not contain any food for thought for you then you are beyond me. I will read along with interest and I will jump in if I have something to offer, but right now you are above my head. I do not believe in ghost in vehicle systems, so your problem can be explained, its just a matter of finding it. - I will be lurking in the background.

Bill and Jim, to clear up my initial post, my voltage at the truck plug with trailer disconnected is the 12.4 volts (truck running, contoller set at 10). The voltage at the battery in the trailer at rest, truck disconnected is 12.6. Resistance at the magnets (disconnected) is 3.5 and resistance in pin junction box (magnets connected is 1.3). BTW, my truck contoller is a 2013 Dodge (factory controller). The brakes on the trailer were equally as bad with my "08 Ford.

 

[Jim.Allison]

I will check this for you. But my truck is in the shop. I hope you can get the answer before that. But if you dont, I will get it.

Has anyone with a 2012/2013 Dodge tested the brake voltage coming from the truck with trailer hooked up, full brake applied and setting on 10 and not moving. As stated in OP, my voltage at the jbox under this condition is very low. I've sent Dodge a question about the contoller (proportional/delayed???) and what would the expected voltage be under these condtions but I have not received an answer.

 

[vangoes]

Jim, thanks for the thoughts. A little background...this is basically a new trailer (1-1/2) yrs old. The braking ability has never been good...it will push the truck in hard braking conditions. All my previous trailers have had much better braking abilities. I have my EVIC set for heavy electric, and controller set on max 10. With trailer hooked up (not moving), I'm only getting 7v at the jbox in the trailer using manual brake lever. If the brake controller is inertia activated to full output, then I dont know if the 7v is normal or not. Thats why I was asking if anyone with this truck/controller has checked their voltage.