Intermitten brakes on 5th wheel

[raptor0818]

Good Morning, left home it was 23 degrees, power cord to pickup was very stiff. Drove a few hundred miles, everything great, all happy, then we heard a ding and then the dash information screen said trailer not connected, check trailer wiring. For the next thousand miles same thing. Felt like the brakes didn't work a few times, then it felt like all four brakes were not working (maybe 1 or two).

Got under the trailer, DW would hit the brakes and I can only hear the right rear brake magnet humming. Looked at the wiring at the axles, found nothing. Going to check wiring at truck this morning. I know I need to check voltage at 7 pin connector. Is it possible that three wheels lost their brakes? I am sure that someone has/had same problem. Thank you in advance for your help.
2019 RAM 3500
2021 ALPINE 3850rd

[JRTJH]

There's something other than the 7 pin umbilical connector on the truck or the umbilical cable from that connector to the junction box on the pinbox.

There is only ONE wire from the 7 pin connector, through that umbilical cable, where it connects to ONE wire in the junction box and then ONE wire from that junction box to the "first brake connection at the axles". That is where it "splits to the opposite side of that axle and also to the rear axle"... On the rear axle, the wire "splits to the opposite side of the rear axle"....

So, if you hear "only one brake magnet humming" the issue is somewhere in the connections "AT THE AXLES"....

If "any brake magnet" is receiving power, then the electrical connections at the truck 7 pin umbilical are intact. Also, if "any brake magnet" is receiving power, then the umbilical cable and the junction box are functional. In other words, if there is power to one brake magnet, then all of those "one wire connections" are intact. Otherwise, there would be NO POWER to any magnet.

I'd suspect, if you have only one magnet humming, then you either "aren't hearing the other magnets" or there's corrosion and wiring problems where that "one wire" splits to go to the opposite side and to the rear axle.....

[raptor0818]

Thanks for replying JRTJH, the way you explain it makes it a little easier to narrow my problem down. If a brake assembly gets worn enough especially the magnet, would that be a possible problem for the check wiring indicator to come on. The indicator to check trailer wiring would come on and off especially when hitting bumps. Thinking about getting under the trailer with a compass and see if I get an deflection on the little compass.

[JRTJH]

I'm not sure if RAM uses the same "trailer disconnect" criteria as Ford, so I'm speculating here....

The truck "trailer monitoring computer" monitors both the output voltage/amperage to the 7 pin umbilical (from the truck's brake controller). It also monitors the resistance in the brake circuit. With those two parameters, the truck's "computer logic" can determine if the 7 pin umbilical is connected AND if the brake resistance is correct (all 4 brakes connected to the wiring)...

If there is an "out of tolerance condition", then the truck's computer will indicate such with a "TRAILER CONNECTOR DISCONNECT" light on the dash....

It may be a problem with the actual 7 pin connector being disconnected/corroded/loose or it may be a problem with the resistance within the brake wiring system/magnets.....

I'd suspect that if you heard "one brake magnet humming" then the truck/trailer connection is operational. I'd focus more on the crimp connectors you'll find on the back side of the brake backing plates and the wires going through the axle beams to the same type crimp connectors on the opposite side of each axle. I'd guess a bad crimp, a corroded or broken wire near a crimp or a wire shorting out where it goes into or comes out of the axle beam....

[raptor0818]

Thank you for responding and spreading your knowledge, it is surely appreciated. Will check things out a little more and see where it goes. Hate doing repairs like this on the road, 1500 miles from home.

[CedarCreekWoody]

Check the pins on the 7 way connector. Clean them good. Make sure the female connectors are closing firmly on the males. You likely need to take a small screwdriver and bend them back to secure.

[NH_Bulldog]

Another thing to consider is that most factory brake controllers (in the truck) are speed and inertia activated. Under a certain speed or at a full stop, you will not get full power to the trailer brakes. While having someone press the truck brake pedal will get you some activity at the trailer brakes, the best way to test is to pull the breakaway cable pin from the breakaway switch and that puts full power to the trailer brakes.

[flybouy]

Easiest test I know is to pull the pin on the trailer emergency brake and pull the trailer forward. If one wheel is locked up and 3 wheels turn then it's likely a broken wire(s) on the trailer. If all 4 wheels lock up then the wire from the emergency pin switch to the brake magnets is good.

[ChuckS]

I would simply use your Hyd leveling system and lift one side at a time just enough to clear the tires off the road ( just one side of RV at a time )..

Now pull the emergency brake control pin and try to spin the two tires that are off the ground

Lower that side and raise the other side and do the same test

Be sure to reinstall brake control pin

If any tire spins when off the ground you know where the issue is.

This test would take less than 10 minutes even with the Alpine hooked up to the truck to test

** BE SURE TO DISCONNECT RV TO TRUCK 7 way cable PRIOR to the above test

** If all four tires spin then you will need to dig further as your issue is (ON the RV wiring side )..

Most likely if all four brakes are affected then right inside junction box at the pin box is where I would start my checking for broken wires, etc

The connections inside that junction box are less than stellar for the 7 way wiring cable harness

Image from my Alpine pin box junction box.. second image is standard wire color code wiring on your Keystone

[Stircrazy]

Originally Posted by NH_Bulldog

Another thing to consider is that most factory brake controllers (in the truck) are speed and inertia activated. Under a certain speed or at a full stop, you will not get full power to the trailer brakes. While having someone press the truck brake pedal will get you some activity at the trailer brakes, the best way to test is to pull the breakaway cable pin from the breakaway switch and that puts full power to the trailer brakes.

I know on my ford it gives full power (whatever you have set for the gain anyways) when you step on the brake when stopped. would be silly not to if you had to stop on a steep hill. anyways I used to pull the disconnect, but I don't anymore as they are not made as robust as they should be for frequent tripping. By squeezing the brake controller tabs I can lock the trailer brakes for doing my tug test and such when I hook up.

[NJ High Country]

I had the check trailer wiring every 30 seconds a couple years ago. We were on our way to Acadia, got as far as saugerties New York. The root of the problem was the household lamp grade wiring inside the axle tube. I trouble shot everything others mentioned above. The picture shows the wire was kinked inside the axle tube, and over time the bumps down the road wore away the insulation. I replaced the wiring on both axles. It was easy and was the fix.

[NJ High Country]

My wife also reminded me that one of our axles was missing the the clips from the magnet inside the drum. The lamp cord and failed wiring inside the drum creates an arc and sends the signal check trailer wiring.

[raptor0818]

Good morning, I jacked up each wheel and had the DW hit the brake pedal, three out of four wheels stopped, left rear didn't. While at each wheel I thought it would be wise to adjust brakes, even though they are nev-r-adjust brakes. Then I cut back the wire insulation at the magnet of the bad wheel and checked for voltage as DW applied brakes, 4.7volts. After removing the hub, there were the bare wires at the magnet. I cleaned wires, coated wires with liquid tape, repacked bearings and reinstalled everything. Big mistake, should have tried the magnet for operation before reinstalling everything. BECAUSE IT DIDN'T WORK. I have ordered a new magnet and let's hope that's the problem, can't visualize anything else wrong since there was voltage at the magnet. By the way I wrote something like the about paragraph the other day, did something wrong and it didn't get posted, so here is another response.

[Stircrazy]

Originally Posted by NJ High Country

I had the check trailer wiring every 30 seconds a couple years ago. We were on our way to Acadia, got as far as saugerties New York. The root of the problem was the household lamp grade wiring inside the axle tube. I trouble shot everything others mentioned above. The picture shows the wire was kinked inside the axle tube, and over time the bumps down the road wore away the insulation. I replaced the wiring on both axles. It was easy and was the fix.

inside the axel tube.. did you just decide to pull it out and check it?

[raptor0818]

Where the household electric extension cord wire comes out of the axle is where I made the cuts. Cuts were made just after the electrical connections, close to the magnet, so I could ensure that the connections were/are ok.

[NJ High Country]

Originally Posted by Stircrazy

inside the axel tube.. did you just decide to pull it out and check it?

[NJ High Country]

Originally Posted by raptor0818

Good morning, I jacked up each wheel and had the DW hit the brake pedal, three out of four wheels stopped, left rear didn't. While at each wheel I thought it would be wise to adjust brakes, even though they are nev-r-adjust brakes. Then I cut back the wire insulation at the magnet of the bad wheel and checked for voltage as DW applied brakes, 4.7volts. After removing the hub, there were the bare wires at the magnet. I cleaned wires, coated wires with liquid tape, repacked bearings and reinstalled everything. Big mistake, should have tried the magnet for operation before reinstalling everything. BECAUSE IT DIDN'T WORK. I have ordered a new magnet and let's hope that's the problem, can't visualize anything else wrong since there was voltage at the magnet. By the way I wrote something like the about paragraph the other day, did something wrong and it didn't get posted, so here is another response.

If you reconnected and reinsulated the brake and it still didn’t work, then the issue must be upstream of that area. Thats why I ended up pulling the wire out of the axle for inspection. I replaced that with a heavy duty extension cord on the outside of the axle. I soldered everything and used shrink wrap to protect the connections. Now it’s easier to inspect and repair if necessary. I ran the new external wide on the top of the axle tube so it’s protected.

[markdol1]

Hey bro i have a ram 3500 and went nuts blaming the truck components ,It wound up being a bad/worn magnet because the brake shoe adjuster fell down into the drum and the magnet stuck to the inside of drum face and wiped the surface down. I found the ohm meter on the magnet showed the problem! New magnet and i was back in business, by the way the wires at the axel tube hole SHOULD BE BETTER INSULATED FROM WEAR KEYSTONE REPS!

[CedarCreekWoody]

Originally Posted by markdol1

Hey bro i have a ram 3500 and went nuts blaming the truck components ,It wound up being a bad/worn magnet because the brake shoe adjuster fell down into the drum and the magnet stuck to the inside of drum face and wiped the surface down. I found the ohm meter on the magnet showed the problem! New magnet and i was back in business, by the way the wires at the axel tube hole SHOULD BE BETTER INSULATED FROM WEAR KEYSTONE REPS!

Sorry bro, no Keystone reps around here.

[markdol1]

you are correct .rams indicate check trailer wiring message and shows no trailer connection icon. if there is a fault other than truck circuit