Here is how I did it, exactly. I took copious notes, as I know it bothers other folks, too. DRL's suck when you're pulling into/away from a star party (astronomy). It takes as long to read as it does to do it, but tweaking things like this can be ultra-dangerous in any modern vehicle.
As posted on the Yahoo! Groups suzukigrandvitara board back in Sept. 1999.
I know there are a few people on the board who, like me, truly
dislike the daytime running lamps. Here's how to extinguish them
without any tools or permanent, harmful, modifications:
Reach up past the right side of the steering column, under the dash.
About even with the bottom of the A/C controls, between the column
and the center radio-A/C stack, you'll feel two rectangular boxes,
each slightly smaller than a cassette tape box. One is oriented so
it is taller than it is deep. This is likely the first one you'll
feel, it has a connector coming out of the bottom. This one isn't
the evil DRL relay.
Move your hand slightly to the left and forward towards the
firewall, go up just a bit more, and you'll find a relay box which
is flatter and oriented to be longer front-to-back. This is it!! On
the bottom is a connector. The connector, a 9-pin, has release
buttons on it's side, like most push-in multiple-pin connectors.
Push in the release levers gently, and pull down to remove. Let it
dangle, should you ever want to reconnect (yeah, right).
Get in, start the engine, notice, no DRL's. Celebrate appropriately.
Think about how much longer your headlight bulbs will last. Enjoy no
longer being a nuicance to others or standing out in a pack of fast-
moving vehicles. ;-)
There is one side effect of your procedure though. Now when you pull
the parking brake, the brake light on the dash board does not
illuminate.
To correct this tie pins 3 and 8 together on the connector you just
pulled out. Here is a diagram of the connector viewed from the
front, with the wires coming out from the back:
[1][2]___[3][4]
[5][6][7][8][9]
For your information the following is a summary of each pin's
function (as best as I can interpet from the wiring diagram (Suzuki
PN 99512-65D00-33E)
[1] - When grounded turns lights on. If the dimmer/passing switch is
in the lo position, then the low beams will come on, if the switch
is in the hi position, then the high beams will come on. No other
lights are affected by grounding this pin, and it works irregardless
of the ignition being turned on or not. In fact this pin is tied
directly to the ground side of the headlights.
[2] - Not connected.
[3] - This pin is grounded when the parking brake is applied.
[4] - This senses weather the engine is running or not by being tied
to the generator. If the engine is running, then 12 Volts appears at
this pin, otherwise with the engine off, it is at 0 Volts. Note
these voltages are measured with the connector removed from the DRL
controller.
[5] - Tied directly to the 20A IG Meter fuse. So this is always at
12 Volts.
[6] - Not connected.
[7] - Tied directly to ground.
[8] - Tied to the brake light in dash. The other side of the brake
light is tied to the 20A IG Meter fuse. Grounding this pin, which is
what happens when the parking brake is applied, turns the brake
light on.
[9] - This pin goes to the optional fog light connector. It is
grounded when the headlights are on. I'm not too clear on exactly
how it works yet.
Below is the color of each wire (Base color/Stripe color):
[1] - Red/White
[3] - Violet/White
[4] - White/Red
[5] - Black/White
[7] - Black
[8] - Violet
[9] - Gray/Black
Note, you could probably turn the DRL off by removing the wire
leading to pin [1] however, I found it easier to remove the
connector and rig a wire with a tab on each end and stuff it into
the connector. This should make re-assembly a bit easier as well.
Edit: I found a bent paperclip works better than a wire with connectors
on it. It'll never fall out, and if you're careful in bending the paperclip, it
won't likely ever touch anything, either.
Oh, and yes if you want to turn the DRL back on, then simply turn
your light switch (on the steering column) two clicks forward.
All of this is based on up to the 2001 model year, though it likely
works on all of the 2nd generation GV's.