How to test our electric brakes?

[jada sharp]

Hi amazing community of knowledge and information. So grateful this site exists!!

We bought our 1972 Overlander a couple years ago and we have just began our adventure in restoring. Would just like to say we are so happy this website exists for the people like us who do not have or want to spend $20k paying someone else to restore their airstream. Side note, we are definitely newbies and have a lot of friends that are helping, but please forgive me if I do not use or know all the proper terms and information. Learning as we go.

Having just started (so haven't even begun with the inside or air conditioning or oven, fridge, etc), we wanted to make sure we got it to a point where it was safe to tow.

We spent a couple of days getting all the left blinker, park lights, 7 way plug, weight distribution hitch all sorted out. We packed the wheel barrings, checked the magnets which were good and replaced a couple of springs.

The next step was to connect and check our brake controller. We bought the prodigy (which we have now been told we could have just as well gone with a cheaper one and it would have done the trick) but water under the bridge.

The problem we have run into is that when we checked the wiring behind the tires there was no electricity going to it. What is the best way to check these? Turn the truck on and press the brakes? Check the wires to see if they are hot when the brakes are on? Connect the prodigy up and check it then? Lift one side of the airstream and turn the wheel and then press on the brakes? See if they stop?

And if the wires aren't working, what would be the next recommended step? I've discovered "feeding" a new wire through to the front panel is not a realistic option. It is impossible to see where any of the wires go so we thought we might have to pull the panel off the bottom of the airstream?

I hope this isn't a silly question and we are going back to check the brakes again today and see if during the daylight a solution presents itself.

THANK YOU!!

[Lumatic]

First pull your breakaway switch and see if that applies the brakes. That will tell you if your wiring is OK. If that checks out make sure you are getting power where your umbilical plugs into your tow vehicle. If that is OK I would suspect the 7 way umbilical wiring does not match the trailer. In 72 Airstream wired the 7 way their own way. Now all trailers and tow vehicles are wired to an industry standard. If that is the case there is 2 ways to fix it: 1. change the wiring configuration at the 7 way connection box inside the front of the trailer 2. Change the wiring configuration in the umbilical cord itself.

[n2916s]

The Prodigy is an inertial controller. If you are not moving, applying the brakes in your tow vehicle will not activate the trailer brakes. But, using the lever arm on the controller will.

The easiest way to check is to hold your basic compass next to the wheel you are checking and activate the brakes using the lever arm on the controller. When you apply them, the compass should swing (due to the magnetism in the brake coils).

[rmkrum]

Originally Posted by jada sharp

Hi amazing community of knowledge and information. So grateful this site exists!!

----------snip--------------

The next step was to connect and check our brake controller. We bought the prodigy (which we have now been told we could have just as well gone with a cheaper one and it would have done the trick) but water under the bridge.

-----------------------snip-----------

THANK YOU!!

I would politely disagree with whoever told you that. The Prodigy is a very smart brake controller, and the inertial-activated system in it seems to be easy to tune to match the trailer and tow vehicle characteristics. Don't feel bad about buying a very good brake controller...

When you are troubleshooting the brakes and umbilical system, look on the eTrailer website for standard 7-blade wiring diagrams to help guide you. You will need a multi-meter or test light to sort out the wiring, as someone else pointed out, Airstream did NOT use standard wiring in '72. Use your truck as the reference and go from there..

[Al and Missy]

Originally Posted by jada sharp

...

The next step was to connect and check our brake controller. We bought the prodigy (which we have now been told we could have just as well gone with a cheaper one and it would have done the trick) but water under the bridge.

The problem we have run into is that when we checked the wiring behind the tires there was no electricity going to it. What is the best way to check these? Turn the truck on and press the brakes? Check the wires to see if they are hot when the brakes are on? Connect the prodigy up and check it then? Lift one side of the airstream and turn the wheel and then press on the brakes? See if they stop?
...

THANK YOU!!

First, welcome to Airstreaming and AirForums. When you report back, bring pictures.

Let's take this one step at a time. First, assuming you meant the trailer brake wires, there will be no power there unless and until the brakes are applied.

You didn't say which specific brake controller you bought, but assuming it is the Prodigy P3, it has features that can be used to do some brake testing if needed, but most of the below is generic to controllers.

Second, read and re-read the manual for the Prodigy.

After you fully understand it, it is time to do some testing. Plug the trailer into the truck. Start the truck. The P3 should respond when it detects that the trailer is connected. Now you need to check the setup of the controller for your trailer. You should probably use "Light Electric". Set the BOOST to OFF, or zero, I don't remember the exact terminology and set the gain to around 5 (not critical). Once setup is completed, Press the lever on the controller to fully apply the brakes. You should see an indication on the display that is proportional to the amount you apply the brakes with the lever.

Assuming all this is good, take the trailer out on a lightly traveled road or to a large parking lot. Drive 25 mph and fully apply the brakes, again with the brake controller lever only, not the truck brakes. Do they work? You should feel the truck slow down when you apply the brakes. Do they lock up and skid the tires? If so, turn the gain down. IF not turn the gain up until the tires skid and then turn it down slowly until they don't. Set up this way you are getting the maximum proper braking power from the trailer.

If all this is good, you still need to test the breakaway switch on the trailer tongue. Jack up a wheel so you can spin it by hand. While the wheel is spinning, pull the cable to activate the breakaway switch. The wheel should stop spinning almost immediately.

Now you know how to evaluate your brake setup. Test it and report back results so we can help you find any problems.

Al

[jada sharp]

Thank you so much for the replies! They all sound so much more promising than where my head was going. Was dreading the worst, but we are heading over at 5 to give it a shot. Will report back and let you all know how it went! Fingers and toes all crossed!!!

[cwf]

Check your GROUNDS...

with trailer alone, nothing connected, BATTERIES in place, check voltage at the breakaway switch... make SURE you get power INTO and LEAVING the switch!!! Sometimes switches fail...

We found the grounds on our 1999 were in bad shape. Repaired...
Found the previous owner used "wire nuts" on the wires at the brake magnet and elsewhere... Repaired...

Do not leave the breakaway switch enabled very long.. a minute or so only, then shut off an let it cool.

Kudos for being attentive to the brakes... great work!

[Action]

Originally Posted by cwf

Found the previous owner used "wire nuts" on the wires at the brake magnet and elsewhere... Repaired...

!

Wire nuts on the wires to the brake magnets is an acceptable practice. If connected correctly and most are a wire nut will work for the entire service life of the brake magnet. Airstream may not be using them now and they did for a very long time.


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[jada sharp]

So I forgot that sometimes when you relay information from one party to another it doesn't translate correctly. The family friend that was helping us has been working on horse trailers for 30+ years and so trying to tell him what to do got a little tricky. Saying that, he did explain that what he was doing with his battery that he was using, there should have been power to the wires behind the tires.
After a couple days of messing around and testing things and trying different things, we finally decided to just run a new wire along the bottom of the airstream. I know some people will probably say that is totally wrong and might eventually have it fixed correctly but we didn't have to add any holes to the bottom or anything. We ended up running alongside the gasline that led all the way back to the tires. Most importantly, it worked and we were able to successfully and safely tow it on it's first 6 hour trip over the Techachapi mountains. In the dark. With our 1994 Ford. And my first time towing anything ever, so I felt pretty happy about it.
Thank you again for all the advice!! I have a feeling this forum is going to be at the top of my search pages for a while.
Excuse the video and language. The original video was too big to upload here so it's a pull from our INstagram story.

[carl2591]

if you use wire nuts put some, try to fill it up, dielectric grease in the base after turning good and tight. that help keep water out of the connection which causes corrosion and loss of signal over time.

I used some butt splices putting both wire in one end, some of the heat srink on the whole thing and dielectric grease in the end of butt splice after crimping the wires. good to go..

Originally Posted by Action

Wire nuts on the wires to the brake magnets is an acceptable practice. If connected correctly and most are a wire nut will work for the entire service life of the brake magnet. Airstream may not be using them now and they did for a very long time.


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