Could it be possible the low beams are burnt out?

 

that's what I thought when I dropped in a pair of new bulbs.

 

The DRL circuit pretty much has zero effect on the low beam circuit, with 1 exception.

If you have a volt meter, see if you have voltage at the 2 15A low beam fuses (labeled "Head LP (RH or LH) Lwr). Those should only be hot when the headlights are suppose to be on.

If you get voltage, start checking wiring an connection to the bulb itself, its a straight shot from that fuse to teh bulb, then bulb to ground.

If your not, you need to check the relay. The DRL No. 2 Relay in actuality is the relay that powers the low beams and disables the DRL by energizing No 3 and No 4 relay. Is the DRL turning off when you turn the headlights on? Also are you sure the high beam isn't just the DRL coming back on? Is it noticeably brighter?

 

yah I'm 100% sure because I do see the difference in lumen when I switch between HB and DRL. Also, DRL don't come on with marker lights.

Don't know where I left my volt meter, would a 12v battery test lights do the trick?

 

Yes it would (test light). Your just seeing if you have power at the fuse

 

Finally was able to test this, there's power on the two 15a fuse to the right of this diagram but regardless of how I set the light switch, I get no power the two 10a fuse to the left.

 

I didn't have time to study the headlamp circuit for HL's w/ DRL, but it looks like DRL-only mode runs the HIGH beam filaments in series, and uses DRL relays to reshuffle the wiring to put the HIGH beam filaments in parallel when turn stalk switch activates HIGH beams.

As for LOW beams, the HEAD LAMP relay powers the LOW filaments and also juices DLR 4 relay.

The first thing I'd do is swap HEAD LAMP relay with one of the DLR relays. They appear to be identical relays.

If the LOW beams work, then the original HEAD LAMP relay is shot. If LOW beams are still out, then chase an issue with ECU connection to relay (relay socket, socket wiring, etc.).

 

You're correct on the relay part, I've swapped all 3 relays around and high beam and drl all works visually as well as I can hear the clicking of the relays on the passenger side. The relay in the driver side fuse box never click. Things are beginning to get real complicated here. Any suggest on how/where to start with the ECU etc...? It's very strange that both lights are gone. FWIW, the problem started with one side years ago, couldn't figure out the issue so I disabled the fogs and tapped some 9006 socket to them and use them for the one headlight. I just did the same thing with the other side so both of my headlights are switched with my fogs.

 

Both low beams can be out because they are wired together off of the relay.

Assuming the HEAD LAMP relay isn't actuating and you're sure the relay is good....

The socket and/or the relay pins should be numbered....

Pin 1 and 5 should be a constant +12v. Pin 2 will probably be 4 to 12 volts with the headlight switch OFF and near 0v with the headlight switch ON low beam.

If pin 2 doesn't change at all when you cyle the headlight switch, then you have to determine whether the headlight switch , it's wiring, the ECU or it's wiring, or the socket and it's wiring are at fault. These steps can be very tedious without a service manual with wire color codes and detailed schematics plus a fair DIY resolve.