elecronic brake conrol sending voltage all the time?

[vanoverp]

Well, my issues continue to surface

Just out of curiosity, I checked the voltage on my new brake controller today. I put a ground to the ground terminal on the truck side of the plug and the other end of the voltmeter to the brake prong in the plug (blue wire). To my suprise, I am getting a tad over 4 volts to the brake prong even when the brake controller is not connected to a trailer. This could be normal, I don't know. I know that the controller sends a signal looking for a trailer connection, and for all I know, this is the 4 volts I was finding on the volt meter. Perhaps when the trailer is actually connected, the 4 volts goes away. I don't know about this crazy stuff....

I had my daughter go ahead and press the switch on the controller in the truck all the way down. My voltmeter shot up to 12, or just a tad over 12 volts. So that sounds good....

Any ideas what this 4 volts is????? Thanks so much for your help. This website is great.

 

[RobertN]

A floating node on the output of the controller. Not unusual for electronics, unless they have a pull-up or pull-down resister in the circuit. Then it would low unless actually switched high. Just a guess, but probably a decent guess...

 

[JB4310]

Did you check any of the other terminals? I had the same question when I was showing voltage on every terminal.

I was supposed to check with light but haven't yet.

http://www.tractorbynet.com/forums/trailers-transportation/140756-trailer-wiring.html?

JB.

 

[mlauk]

What brand/model controller do you have? Is it set up correctly? If it is set up to aggressively, the brakes could be on at a lower voltage.

 

[vanoverp]

I will have to check the other terminals and see if there is anything else "alive". I know the accessory post is alive, but it is supposed to be. I haven't checked anything else.

It is a Hopkins Agility proportional controller. I do have it set fairly aggressively

 

[mlauk]

Never mind, I have an old school controller that you have to "level" and then has 2 adjustments. The brakes can be activated if not set properly.

It looks like your model does not require leveling and only has one adjustment for amount of power.

 

[wkpoor]

Controllers can and due go bad.
Last year I had a controller that would spike the trailer everytime the brake was applied regardless of setting. I suspected it was a 12V flash from the controller and was only visible with a test light. VOM wouldn't pick it up. Went to my dealer and he tested it and told me I was full of S****t. I said well sell me another controller anyway. I installed the new one and problem was solved.

 

[Steveguy]

I wouldn't condemn the controller yet if you haven't even hooked it to the brakes. I've seen many instances where solid state relays or scr's will leak voltage through them. Your meter is a very high impedance, so it won't pull down the voltage. At work we sometimes use a small resistor across a solid state device to pull that voltage down. The current is very small. When you hook up your brakes you have several coils hooked up (the electromagnets in the brake units at each wheel) this should pull down that voltage reading, but shouldn't be enough current to really build a magnetic field and actuate the brakes. If it does energize the brakes, do like the other poster said, buy a new controller.