Trailer Brakes INOP

[chaseav]

Long story short: 3-4 weeks since last tow, no (known) outside influences, trailer brakes are not working. Lights work, even brake lights actuate, Tow Vehicle is supplying power... just no trailer brakes. I have a multimeter but no idea what to do with it!

The back story: Just brought my AS back from the dealership, 1.5 hour drive, everything worked great. Spent $3,000 on it, fixing anything that could have been wrong and almost nothing was; new tires, resealed roof, inspected everything. I did it all in preparation for the journey to EAA's AirVenture now coming up this weekend... those campsites are extremely expensive (ugh) and DO NOT WANT TO MISS THIS due to INOP brakes. But it's REALLY hard to get to the dealership without BRAKES!

It's been a long time since I've posted on here but someone always came up with a very simple fix, often times user error and not mechanical malfunction. Any help appreciated!

[GMFL]

Things to try…

Pull the pin from emergency disconnect switch. See if you have brakes. If you do, then the problem is likely the Tow Vehicle.
If you still don’t have brakes then it’s likely the trailer.
This will get you a starting point.
Let use know tte results and we will go from there.

[RTOS_LLC]

I don't know your skill level so here is a detailed test procedure.

Per prior individuals response, pulling the break away will apply your trailer battery voltage to your brakes. If switch is good and if battery is charged all brakes should activate indicating wires from break away switch to all brakes are working. Assuming this is the case find a trailer connector drawing on line as there are many to identify each connector pin. The trailer light pins have nothing to do with the traile brakes, all you care about is blue wire and ground. I am assuming you are using and aftermarket brake controller and it is plugged into tow vehicle connector and am assuming you don't have a trailer brake short and brake controller is turning off. So the first question;

Is if blue wire is making it to the trailer connector of tow vehicle?

- Put your meter on DC volts.
- Connect volt meter ground to connector ground and volt meter positive top blue wire pin.
- Start vehicle and set brake controller gain to maximum value, usually 10.
- While watching voltmeter have someone apply full manual brakes on brake controller.
- You should see tow vehicle battery voltage.

*Assuming you are seeing battery voltage you likely have a poor connection between tow vehicle blue wire and/or ground and the trailer connector.
*If you don't see battery voltage when manual on full, check blue wire output from your brake controller.

If blue wire was present at tow vehicle connector question two is why isn't it making it through trailer connector and to the brakes?

- Clean pins and make sure connector is fully inserted.
- Find a location to check blue wire at the point where it meets up with the break away switch.
- Repeat prior test.

*If voltage present you likely had a connector issue, which "may be intermittent".

If no voltage at trailer blue wire location being checked, next check blue wire voltage out of trailer connector.
-If no voltage present, either clean, insert better, or replace connector with a "compatible connector".
-If voltage is present you have an open blue wire between connector and break away switch location referenced above, so find open wire and fix it.

You can change check voltages where ever you like, in what ever order you like. You are just looking for where the voltage is lost.

I hope this helps.

[chaseav]

Thank you all for taking the time to respond. I carried out some troubleshooting procedures and ended up choosing the most telling and simplistic... I grabbed a buddy's truck, hooked it up and lo and behold... trailer brakes worked fine!

So that very quickly ruled out the AS as the problem and the finger got pointed at the Tow Vehicle; a 2007 Chevy Avalanche WITHOUT an integrated brake controller. I am new to the area but turns out, there is a great trailer service company here who took about 10 second to diagnose my problem as a bad, aftermarket Trailer Brake Controller. It simply wasn't putting out enough amperage (voltage?) to even actuate the brakes.

New controller installed, everything works great! Total cost, $56! Sidestepped that land mine!

PS- I did get a private message from a gentleman on this forum who offered to speak with me about this. We did, and he was a huge part in troubleshooting. Once again, this forum has saved my bacon.