Electric brakes mystery
I hooked up the Big Toyhauler the other day. All lights and signals function correctly. But - no brakes. Hmmm.... I am a bit of a dummy when it comes to things electrical. Here is what I know ...
Forum Discussion
wa8yxm wrote:enblethen wrote:
Should not have continuous power on blue wire. It should only have power when brake pedal is applied.
What kind of tow vehicle?
Exact model of brake controller?
Actually many controllers put continous power on the blue wire, OPEN CIRCUIT (Trailer not plugged in it will read 12 volts if the controller sees that 12 volts (Well battery voltage) when it's not calling for brakes it flys the fault flag to alert you to a problem.
IF you put a load on it (Say a test light in parallel with your volt meter) you will see it go down like a rock in free fall for it's a high resistance feed... if you plug the trailer in the voltage approaches zero (you won't be able to measure it) I doubt it's light the test lamp.
One of the reasons you need both a volt meter (HIGH resistance or high impedance load (The two words apply to DC and AC respectivelly)often well over 100,000 ohms) and a test light (Low resistance load often closer to 1-2 ohms)
I wondered about 12v being "normal" with no trailer - I can't say if that is the case with the two controllers I mention in my reply above. I am calling Hayes tech support today.
