M1101 Low Voltage on Left Hand Brake/Turn

[ahawksfan]

Before I tear in to my newly purchased M1101 I figured I would ask the experts. I am running a flat 4 wire connector from the vehicle to the stock M1101 harness. After changing the 24V bulbs to 12V bulbs (thanks SS for the part numbers 97 and 1156 as I recall). Got the following wired up:

Flat 4 Pin <-> 12 Pin
Yellow <-> B as Left Turn/Brake
Green <-> J as Right Turn/Brake
White <-> D as Ground
Brown <-> E as Running Power Tail/Marker Lights

I only ran in to two problems. One of the LED marker lights is flaky (goes on/dim/off so it is probably a bad connection or LED marker failing). But the bigger problem is the Left Hand Turn/Brake bulb is not working. Swapped it with the right side bulb which was working and the problem persisted in the left. I then checked voltage at the bulb and I am only seeing about 9.5V where the right side is giving me 13V. I then check the voltage out of the vehicle wiring harness and the point of connection to the M1101 12 pin connector - in both cases it was 13V when brake was depressed.

Any suggestions on what I should do?

Thanks in advance!

Ed

 

[MWMULES]

First would be to clean the grounds at the light fixtures.

 

[goldneagle]

Check the grounds on the LED marker lights. On my trailer the front amber LED was intermittent and sometimes very dim. When I opened it up I saw it was attached by 3 rivets and one screw. The one screw must be ground connection. It was not tightly secured. I tightened it and hope I get a better ground next time I hook up the trailer.

 

[juanprado]

The older lights are grounded through both mounting bolts. Make sure they are clean and those star washers are biting into clean metal. Double check the wiring plug is nice and snug at the light also.

 

[ahawksfan]

Thanks for the advice! I will check the grounding.

* Update * - Thanks everyone it was a ground issue. I changed the bolts (7) holding the lighting bucket on and added star washers for a grounding boost and that solved my problem. On to a permanent wiring connector.



Ed

 

[KansasBobcat]

I use dielectric grease on all connections. It prevents corrosion and makes it easier to connect/disconnect rubber plugs. I usually replace all old star washers.