Forum Discussion

Executive45's avatar
Executive45
Explorer III
May 05, 2015

Daylight running lights issue

I have a problem that has me stumped. One of my headlights is very dim. First thought was a bad ground. Took headlight apart and checked everything. Turned on the headlights and bright as day. Thought I had the problem licked. Came into another campground and a camper mentioned one of my headlights was dim...what the heck?

Turned on the headlights and bright as day.!! Thought maybe the coach was possessed. Anyway, I finally found the problem.

The headlight is ONLY dim when the daylight headlights are ON.

If I turn on the headlight switch the lights are bright. Turn that switch off and start the coach and the one headlight dims. I'm not familiar with a daylight running light circuit so I'm at a loss as to how to trouble shoot it. Any ideas ??? TIA.....Dennis
Class A
  • Executive45's avatar
    Executive45
    Explorer III
    May 06, 2015
    I located the DRL module in the front run bay compartment. Disconnected it from the harness, put some dielectric grease in the fitting and put it all back together. Seems to be working ok now....BTW, the parking brake has to be OFF and the coach needs to be in gear for the lights to work...thanks to all for your input....Dennis
  • dodge_guy's avatar
    dodge_guy
    Explorer II
    May 05, 2015
    Are your high beams working OK? Most DRL's use the high beam bulbs on a lower voltage. So when you turn on the headlights the DRL's are turned off.
  • ScottG's avatar
    ScottG
    Nomad
    May 05, 2015
    Often times DRL drivers power the headlights with a partial duty cycle. The light appears normal but in actuality it is getting small pulses to stay lit. My guess is there's an issue with the driver itself.
  • fourmat's avatar
    fourmat
    Explorer
    May 05, 2015
    need schematic for headlight circuit Drl module is USUALLY on the firewall below steering near fuse panel but I have seen them under hood as well. Small square or rectangle box usually 5to6 wires going to it common is blue red green orange yellow black most of the time labeled DRL
  • Executive45's avatar
    Executive45
    Explorer III
    May 05, 2015
    fourmat wrote:
    does it go off when you set P/B


    IDK....I'll have to give that a try. I also don't know where to find the DRL module or what it might look like. I'll have to call Monaco since it appears DRL modules come in all sizes and flavors....Dennis
  • path1's avatar
    path1
    Explorer
    May 05, 2015
    My best guess.

    1. Check wires/connections best you can, (wire/connection might be grounding out).


    2. The headlight switch itself, beginning to go bad.
  • fourmat's avatar
    fourmat
    Explorer
    May 05, 2015
    A lot use a DRL module sounds like the dim light is ok its the other side that is the problem with DRL they should both be dimmer than standard night time DRL module may be bad does it go off when you set P/B

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