Tuesday, May 07, 2013 at 08:19
As per Allans response, that link from Darren (text below) is in fact talking about a "no load" condition and a "phantom" voltage as Allan said. You may be good to go as is but always good to do the light bulb
test to be sure.
Question
When I measure the output voltage from EB, EBRH or EBTM on the trailer socket brake pin, with the trailer not plugged in, I read 4-5V. Is this OK?
Answer
Yes, this is OK. The EB brake controllers have a trailer brake circuit detection LED. (When you plug in the trailer, the green LED should light).
If this pin is measured with no trailer plugged in, you will see the trailer brake detection voltage from the LED on the EB. This voltage should only be seen if a trailer is not plugged in or if the trailer brakes are open circuit.
This can be checked by connecting a 5W
test lamp to the pin while measuring the voltage. This should result in the meter showing 0V and the green LED on the EB should light.
A metering voltage may also bee seen on other circuits if the vehicle has trailer lamp fail detection. Likewise, these voltages should only be seen if a trailer is not plugged in or if the trailer lighting circuit is open circuit.
FollowupID:
788575