Diagnosing trailer brake issue

[gnijman]

Originally Posted by 66Overlander

Glad I could help . . but the name is Joe, not Al (no big deal tho).



The Pollak 12-706 is basically the hard plastic "bolt-on" plug (they also make a metal housing version). It is available by number in many places online, including eBay.

In a trailer parts store, you probably won't see the 12-706 number listed, but if it is hard plastic and says "Pollak" on it, that's the one:


And yes, finding one that says it meets J2863 is tough. I remember the engineering drawing for the Pollak 12-706 did not specifically list that spec, but the part measurements all were within the tolerances listed in J2863.

How did I ever get Al?? Anyway, thanks Joe.

BTW, I think the SAE J2863 was updated to J2863 as of July 1, 2016. What was updated I don't know ... the standard is $78 (!) to download in PDF!

Hopefully the Nanaimo trailer hitch place has some plugs (Pollak maybe) that we can try in my truck receptacle for fit.

You'd think someone would have invented a screw together or twist lock plug connector fitting to join trailer and truck. ... like the twist lock and screw-tight fitting for the OEM shore power cable on the AS.

Gary

[66Overlander]

Actually the J2863 plug and receptacle were designed to come apart hopefully without damage should someone forget to unplug after unhitching and drive away. Would hate to pull the wires out from the truck or trailer in such a case. Have to protect the end user from themselves sometimes.

[gnijman]

Originally Posted by 66Overlander

Actually the J2863 plug and receptacle were designed to come apart hopefully without damage should someone forget to unplug after unhitching and drive away. Would hate to pull the wires out from the truck or trailer in such a case. Have to protect the end user from themselves sometimes.

Yep - that's why I walk all the way around the truck before pulling it away from the trailer - and all the way round the trailer before pulling it away with the truck.

Thanks again for all your help and thanks to all the others that helped.

Gary

[shb2777]

Don’t know about your setup but my 07 Classic has electric over hydraulic brakes. So I had to make a pig tale with two brake magnets wired in line to get my 2009 Duramax 3500 factory controller to recognize my trailer.

[GCinSC2]

Well done and even the rare report about the conclusion solution.

Nicely done.

[suncoasteng]

Check all your vehicle outputs first, use a wood nail file combined with brake cleaner to clean all the contact surfaces inside the plug and receptacle!

[TG Twinkie]

Have things changed?
Green use to be tail/running lights.
Red was left turn
Brown was right turn
Blue was brakes
Black was charge line
White was common/ground

[Ivy Lincoln]

I'm away from our trailer or I would send a picture, but I found a fuse in the box where the hydraulic brake fluid is housed down behind the vee in the trailer chassis behind the hitch and the propane tank rack. I cleaned the fuse with electronic cleaner and reinserted it; then the trailer brakes activated when the tow vehicle brakes were applied.

[Ray Eklund]

I had my Right Side brakes quit working. I was getting prompts on the Ford 'Trailer Disconnected'. With Forum Members help, I tracked the 12 volts from the Left Side, that worked, to the right side that did not, but was getting power when the Truck Brakes were applied. I am purchasing both Dexter Brake assemblies and start with New brakes on the Right Side.

I do not want to become an Airstream Service Mechanic... but over time, you have no choice to learn it, bit by bit. Trouble shooting is getting an education.

If you apply brakes from the Tow Vehicle, have someone listen to the slight 'hum' from operating brakes. If you do not get the hum... no power.

As said earlier, pull the Brake Away Switch... hum. Do it quickly and reinsert the 'plug'.

Or as we did, get one wheel in the air, spin and the other apply brakes. Ours would lock up immediately if working. Go to each and make a note if they work or not. It takes some time, but worth it.

I did not realize the right side were no longer operating on this last trip. Spin, brake... and then kept spinning. Whoa... We were on Mountain Roads in western Wyoming at the time!

It is frustrating. You ask yourself... 'Why ME?'. You and I will know a lot more about Dexter Brakes than we want to... but over time, your Airstream friends will have you over for Dinner to... fix theirs.

Al and Missy must be very busy in their 'free time'. They have helped me over the years with their advice.

Like I said... when you figure yours out... stop by.

[GCinSC2]

Originally Posted by Ray Eklund

I do not want to become an Airstream Service Mechanic... but over time, you have no choice to learn it, bit by bit. Trouble shooting is getting an education.

Yup, you wanna play, ya either learn to fix or learn to pay.

I'm trying to keep it learn how and pay for parts.

Ray you're gonna get a chance to learn bearings an seals too if you don't have that Merit Badge yet.

[rmkrum]

Just remember, MacGyver never owned an Airstream, he had it easy...
I still keep my genuine Swiss Army Knife (made by Wenger) close at hand on the road, along with my buddy, Justin Case.

[gnijman]

Originally Posted by Ivy Lincoln

I'm away from our trailer or I would send a picture, but I found a fuse in the box where the hydraulic brake fluid is housed down behind the vee in the trailer chassis behind the hitch and the propane tank rack. I cleaned the fuse with electronic cleaner and reinserted it; then the trailer brakes activated when the tow vehicle brakes were applied.

I've got a 2016 FC 25 FB. I see nothing mentioned in my manual about there being a hydraulic component to my braking system. Anyone know any different.

More on the solution front ...

I dropped by my GMC dealer and inquired about the shaky fit on the plug issue. No one had reported it besides me. They were unaware that GM had flipped the plug arrangement since my earlier 2002. Anyway, I asked their parts department to dig out whatever replacement trailer-end plug they stock/use so I might try it for fit.

They handed me a Curt model 58140. It is made of hard plastic unlike the soft plastic plug that came with my AS. Wow does it fit nice and tight. The locking flange on the truck plug flat also engages much tighter. The service guy agreed. It was all of $10 to buy so I bought it to splice in and try.

I have yet to swap the plugs but I did put an electronic callipers on both new and old plugs. The AS original is 1.631" diameter at the truck end and widens to 1.638" at the flange that engages the receptacle lid. From the face of the plug to the flange is 2.070".

The Curt is actually a bit narrower - 1.598" at truck end widening to 1.608". However it is longer from the face of the plug to the flange - 2.144".

It seems odd that the Curt though measured as narrower actually fits snugger and wiggles not at all when inserted. Maybe that's due to it being made of hard plastic. The higher fit on the holding-in flange looks to be due to the longer dimension on the Curt.

The Curt plug is also single bladed inside the plug instead of double-bladed in the AS original.

My neighbour is very handy with this sort of wiring and is going to assist me on the plug swap. I figure it's worth a try and I have plenty of slack in the cable itself in case I end up having to do yet another swap.

I think I'll also get a strip of velcro (as mentioned by someone earlier in this thread) to secure the lid of the truck receptacle to the plug).

I let you know how it goes.

Gary

[gnijman]

Originally Posted by suncoasteng

Check all your vehicle outputs first, use a wood nail file combined with brake cleaner to clean all the contact surfaces inside the plug and receptacle!

Good suggestions. I use el-cheapo cardboard backed nail files. They are simple to trim with a scissors to give a perfect fit. I use a spray electric contact cleaner.

Gary

[rmatkovich]

Originally Posted by gnijman

I have a 2016 FC 25 that we ordered new and is barely used. Until recently we towed with a 2002 GMC 2500 HD Duramax and always thought our trailer brakes worked fine. My wife is the more experienced tow driver having towed horses in a heavy trailer for many years and she swears she could feel the trailer brakes on AS were applying correctly with the 2002 truck.

We have not used the AS since it was stored late last Fall.

We have just bought a 2018 GMN 3500 Denali Duramax, hooked it up to the AS and the DIS (Driver Info Display) tells us we now have a trailer brake wiring problem.

Here's what we've discovered.

We started with properly cleaned connections on our RV trailer connector wire. We hooked up to set up the brake controller that comes integral to the new truck. The brake lights, turn signal lights and marker lights on the AS all worked fine when actuated from the truck.

The truck manual says that when we connect up we are supposed to get this message in our DIC, ""Trailer Connected". We did not and instead we got "Check Trailer Wiring".

The truck manual said that to determine whether the fault is on the truck or trailer side we should leave the truck running and connected then:
1. Disconnect the trailer wiring harness.
2. Turn the ignition off.
3. Wait 10 seconds then turn the ignition to "ON".
4. If the Check Trailer Wiring message reappears the fault is on the truck side (it did NOT reappear).
5. If the Check Trailer Wiring message only reappears when connecting the wiring harness then the fault is on the trailer side (it reappeared when we reconnected).

So, according to the truck, the fault IF ANY lies on the trailer side.

I checked the fuses in the AS (and checked the AS manual about fuses) and there does not appear to be any fuse on the AS for any wiring pertaining to the trailer brakes. I looked on the fuse panel and below the trailer at the wiring to the wheels for possible inline fusing. (Anyone have any contrary info??).

Since we were only planning to pull out the AS to test for level after adjusting the truck hitch down 2" to accommodate the higher new truck and toddle round the neighbourhood for a gentle test, off we went. (The trailer level was perfect).

We decided to try the truck manual's instructions to have the truck brake controller self adjust for brake gain and see what happened. That required us to accelerate to 32 to 40 kmh (20-25 mph) and while maintaining that speed apply the Manual Trailer Brake Apply Lever so the trucks computer could set the Gain. We did that. We then switched the DIC to the view that shows Trailer Gain which is supposed to show the applied Gain when the trailer is connected and brakes are applied and drive around our area. We applied the brakes on level ground and on fairly steep downhill grades travelling at 50-60 KMH (say 30 mph). My wife says she could not feel any trailer braking and the DIC showed no Gain on its display when she applied brakes.

We then stopped the vehicle and manually increased the Gain on the trailer brake controller to its highest setting (10.0) to see whether that would lock up the brakes (wheel skid) when we drove and applied brakes. We tried it and still felt no trailer braking - no trailer wheel skid - on the same route/speed as before.

At that point we parked the trailer in the yard and opened a bottle of wine.

Does anyone have input on how to diagnose the issue as well as we can out our end before we take it in to our GMC dealer (who maybe can't help with trailer brake issues) or god forbid our RV repair place ("we can get you in in maybe 4 weeks and can you leave it with us for say 3 weeks").

I'm wondering whether I put the probe of a meter into the trailer wire socket of the truck to see whether the truck is sending a signal to the AS brakes. Assuming I find the pin pertaining to the brake how do I do that (one tester probe on the brake pin and the other where? 12v(+)? 12v(-)? The problem is also finding which pin pertains to the brake. Good idea or bad idea? If the truck is sending a signal then what?

Ideas?

Thanks folks.

I would hook the truck back to the AS. Pull the emergency plug ans see if you can move the AS. If you can pull it and the brakes do not lock up then there is a problem with the AS. If they do lock up then the truck is the problem. Good luck.

towing a 2000 34' limited AS with a 1997 F-250 7.3 with 378,000 miles and all works good.
Jim

[rmkrum]

Don’t connect the umbilical when you do this test. Just hitch up only. Some brake controllers do not like being backfed from the AS batteries...they object by leaking smoke in lieu of tears, and immediately quit working.

[66Overlander]

Originally Posted by gnijman

I've got a 2016 FC 25 FB. I see nothing mentioned in my manual about there being a hydraulic component to my braking system. Anyone know any different.

More on the solution front ...

I dropped by my GMC dealer and inquired about the shaky fit on the plug issue. No one had reported it besides me. They were unaware that GM had flipped the plug arrangement since my earlier 2002. Anyway, I asked their parts department to dig out whatever replacement trailer-end plug they stock/use so I might try it for fit.

They handed me a Curt model 58140. It is made of hard plastic unlike the soft plastic plug that came with my AS. Wow does it fit nice and tight. The locking flange on the truck plug flat also engages much tighter. The service guy agreed. It was all of $10 to buy so I bought it to splice in and try.

I have yet to swap the plugs but I did put an electronic callipers on both new and old plugs. The AS original is 1.631" diameter at the truck end and widens to 1.638" at the flange that engages the receptacle lid. From the face of the plug to the flange is 2.070".

The Curt is actually a bit narrower - 1.598" at truck end widening to 1.608". However it is longer from the face of the plug to the flange - 2.144".

It seems odd that the Curt though measured as narrower actually fits snugger and wiggles not at all when inserted. Maybe that's due to it being made of hard plastic. The higher fit on the holding-in flange looks to be due to the longer dimension on the Curt.

The Curt plug is also single bladed inside the plug instead of double-bladed in the AS original.

My neighbour is very handy with this sort of wiring and is going to assist me on the plug swap. I figure it's worth a try and I have plenty of slack in the cable itself in case I end up having to do yet another swap.

I think I'll also get a strip of velcro (as mentioned by someone earlier in this thread) to secure the lid of the truck receptacle to the plug).

I let you know how it goes.

Gary

Hi Gary, SAE J2863 specifies many dimensions, plug diameter being just one of them that can be critical. Perhaps even more critical is the length of the plug from the "lock tab" to the plug face. Some of the worst performing plugs were significantly shorter than spec in this dimension, thus allowing them to "back out" significantly while still being retained. Since you noted the Curt plug is longer than the stock Airstream plug, perhaps it is within spec or closer to spec in this dimension. Also critical is the location of the contacts within the plug body. Some of the worst performing plugs had the contacts recessed into the plug body more that allowed by the spec. Again, the Curt plug might be closer to or within spec for contact location. Good luck!

[gnijman]

Originally Posted by 66Overlander

Hi Gary, SAE J2863 specifies many dimensions, plug diameter being just one of them that can be critical. Perhaps even more critical is the length of the plug from the "lock tab" to the plug face. Some of the worst performing plugs were significantly shorter than spec in this dimension, thus allowing them to "back out" significantly while still being retained. Since you noted the Curt plug is longer than the stock Airstream plug, perhaps it is within spec or closer to spec in this dimension. Also critical is the location of the contacts within the plug body. Some of the worst performing plugs had the contacts recessed into the plug body more that allowed by the spec. Again, the Curt plug might be closer to or within spec for contact location. Good luck!

The Curt plug solved the problem!

Along the way we discovered:
- don't bridge connections in the socket while mapping it or you'll have to replace a few truck fuses
- detaching the trailer battery cables before cutting the plug off prevents the repeat of a shocking surprise and another shower of sparks

Finally, shortening the wire by the length of the plug we cut off meant routing the wire differently through the A-frame of the trailer just a bit. The bottom of the spiffy aluminum propane tanks cover was then in the way. I took the cover off and put a spacer nut and thick washer on the cover's threaded mount and that raised the entire bottom of the cover clear of all wiring. I also sanded smooth the semicircle already cut into the cover's bottom edge for wires to pass through as it was quite sharp. This gave me the little extra I needed to ensure the wire was not stretched when going round corners.

So, I am signing off on this thread. Thank you all for your great assistance.

Gary

[OSU76]

Originally Posted by gnijman

The Curt plug solved the problem!

Along the way we discovered:
- don't bridge connections in the socket while mapping it or you'll have to replace a few truck fuses
- detaching the trailer battery cables before cutting the plug off prevents the repeat of a shocking surprise and another shower of sparks

Finally, shortening the wire by the length of the plug we cut off meant routing the wire differently through the A-frame of the trailer just a bit. The bottom of the spiffy aluminum propane tanks cover was then in the way. I took the cover off and put a spacer nut and thick washer on the cover's threaded mount and that raised the entire bottom of the cover clear of all wiring. I also sanded smooth the semicircle already cut into the cover's bottom edge for wires to pass through as it was quite sharp. This gave me the little extra I needed to ensure the wire was not stretched when going round corners.

So, I am signing off on this thread. Thank you all for your great assistance.

Gary

Our TV is a 2017 Yukon Denali 6.2l A nightmare since purchase of our new AS 2019 25 Flying Cloud Great info on this site but here is the link for the best explanation I have seen yet http://www.rambodybuilder.com/2016/d...ConnCompat.pdf