Troubleshooting Dim Trailer Lamps

Updated 06/09/2011 | Published 06/08/2011

Products Featured in This Question

Peterson Trailer Tail Light - Stop, Turn, Tail - Incandescent - Round - Red Lens - Passenger Side

(1231)

$10.37

Digital Multimeter with 42" Long Test Leads - LED Display

(4)

$23.69

Question:

Everything works fine, right and left turn signal, and brake. The light is not really all that bright during the daytime, I have to cup my hand over it to see if it is on or not. When I take the lens off, the bulb element seems to be barely lit, like it doesnt have enough juice. Just wondering if there is something that is not properly grounded either on the trailer or on the vehicle plug-in. Thanks.

asked by: John K

Expert Reply:

Determining the cause of your dim lamps will be a process of elimination.

I would recommend using a multimeter like part # PT89ZR on the circuits feeding the lamps on your trailer. You should be reading close to 12-volts at each lamp. If you are not, you will need to do some troubleshooting.

Test the pins on the trailer connector on your vehicle, you should be getting close to 12-volts at each pin as its function is activated. If you see a dramatic difference in voltage between the vehicle and the trailer, you should closely examine the trailer.

Check the trailer connector on the vehicle and the trailer. Make sure the connectors are not corroded or damaged in any way. Examine the wiring on the trailer that feeds each lamp. Make sure all connections are secure.

Another possibility would be trying the trailer on a different vehicle. If the lamps are not dim when the trailer is attached to a different vehicle, you have eliminated the trailer as being the problem.

expert reply by: Mike L