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Hi. I have a 2011 Odyssey EXL, 160k miles. Well maintained. My passenger side DRL and high beam is dead (same bulb). I've replaced the bulb and no luck. All fuses are good. Volt meter shows good voltage, but when the DRL or high beam is activated the voltage drops to 0. All the other accessories in the vehicle are working normally (including the driver side DRL and high beam). On older 2010 models there is a DRL voltage modulator, but it appears the 2011 does not have this. If it does, it is not behind the glove box nor steering wheel and a parts search shows no replacement part for this. I'm stumped. How can the harness have normal voltage then drop to 0 when the light is turned on... The alternator seems completely normal. Any help would be appreciated. I have not seen this addressed on forums or technical bulletins. Thanks.
 

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2016 Touring Elite
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The high beams / DRL power comes from the "Relay Control Module" located in the under-hood Fuse/Relay Box located in the back passenger side corner of the engine bay. Power for the Highs/DRLs goes through Fuse 24 (left) and Fuse 20 (right). There doesn't seem to be a separate DRL module anymore. Here's some text from the wiring diagrams:

Daytime Running Lights (DRL)
The DRL circuit is composed of the control circuit board
in the relay control module (in the under-hood fuse/relay
box), the DRL Indicator, the left and right headlights
(high beam), the left and right HID unit (high beam)
(HID), the parking brake switch, the relay circuit board in
the relay control module (in the under-hood fuse/relay
box). The DRL circuit operates with the ignition switch in
ON (II), the headlights off (headlight switch in OFF or in
PARKING position), and the parking brake released.
When the DRL circuit is on, the control circuit board in
the relay control module (in the under-hood fuse/relay
box) and the relay circuit board in the relay control
module (in the under-hood fuse/relay box) activate the
DRL control circuits on and off (duty cycle), which
provides a reduced voltage (approximately 6-8 volts) to
the high beam headlights. This reduced voltage causes
the high beam headlights to come on with a reduced
brightness. The DRL Indicator also illuminates.
NOTES:
• The DRL circuit is disabled when the ignition switch
is turned to OFF (0). To keep the DRL circuit from
coming on, apply the parking brake while the
ignition switch is in OFF (0). When the ignition
switch is turned back to ON (II), the DRL circuit will
not come on until the parking brake is released.
• The headlights revert back to normal operation
when the headlight switch is moved to the ON
position.
So, if Fuse 20 is still good (check with multimeter, not just visually!), there isn't a whole lot else to check. It looks like the relay module is available separately (PN 38850-TK8-A01 for my '16 Elite, not sure if that crosses to your van) if that is the problem.

-Charlie
 

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Discussion Starter #3
Hi Charlie... Thanks for the reply and information. I replaced both fuse 20 and 24 and still no resolution. The harness is hot until the light is turned on and then power drops to zero. It's gotta be a control board, but which one and where?
 

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The harness is hot until the light is turned on and then power drops to zero.
This confuses me a little. What harness is hot? In what conditions? How are you measuring 'power going to 0'?

Power should not be delivered at all to the high beam connection unless the ignition is in the ON position and the parking brake is off. At that point, it should be 'low power' delivered to the bulbs. Based on the description, it s PWM (pulse width modulation) controlled power from the relay module of around 6-8V when a bulb is connected.

When the high beams are activated (either flash-to-pass or constant), full voltage should be supplied to the high-beam bulb connection

The relay/control module is inside the large fuse box on the back passenger corner of the engine bay.





I don't know how easy or hard it is to remove from the fuse box. There are 5 electrical plugs on the bottom of it of various sizes...

Before replacing that, it would be good to rule out other external problems (wiring, bulbs, etc.)

-Charlie
 

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Hi Charlie... Thanks for the reply and information. I replaced both fuse 20 and 24 and still no resolution. The harness is hot until the light is turned on and then power drops to zero. It's gotta be a control board, but which one and where?

Did you ever figure this out? I'm running into the exact same problem on my 2012 Odyssey.
 

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How did you fix the issue? I think I am having the same issue. One side of the bulb connector has voltage so I’m thinking it’s a ground issue.
 
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