Enable/Disable Daytime Running Lights
Thanks to Don
Smith for contributing this article.
Why was this article created?
There seems to be a lot of confusion about Daytime Running Lights (DRL) on the Ford F150
trucks. How to enable them, how to disable them.Can I use the existing wiring harness to do this
or do I need the Ford "kit" to do it? Where do I get the parts to enable them? What
are the part numbers? The following article was created to help you with enabling or disabling DRL for
your truck.
How DRL Works:
1999 and newer:
From the manual: The DRL are implemented by using the low beams at a reduced voltage
of approximately 80% system voltage. This is accomplished by inserting a DRL resistor in series with the
low beam filaments. When the headlamp switch is engaged, the daytime running lamp function is disabled
and the low beam filaments receive 100% system voltage.
What it means: The DRL Relay Block enables
power to the low beams and the resistor changes the
voltage going to the low beams from 12 volts to 10 volts
thus making them dimmer. In trucks that do
not have DRL a loop-back
plug is in place of the Relay Block which provides
ground to the Multifunction Switch (Steering Column
High/Low/Flash to Pass switch) so the normal low and
high beam lights still work.
1998 and older: (Sorry
people... very limited information on this one)
From the manual: The DRL system
is designed to turn the high beam headlamps on at a
reduced output without illuminating the high beam
indicator. The system is activated when the ignition
switch is in the ON position, the headlamp switch is in
the OFF position, and the parking brake is released.
What it means: The DRL "Module"
does everything. It does not use a resistor
but instead uses switches to provide lower voltage to
the High beams. Not sure about to much more
like wiring, etc. All I know is that it's
not compatible with the 1999 and newer layout. I do however have the part number for the module:
F65Z-15A272-AA. It's location is
around the same area as the resistor on the 1999 and
newer trucks.
Some History of my
search...
I have spoken to the service department and parts
department at my local Ford Dealership (where I bought
the truck) letting them know I wanted to enable DRL on
my 1999 Ford F150 truck. I was told that
this could be done by purchasing the DRL Kit for about
$55.00. I did just that and found that I
would have to hack into my wiring harness to get this to
work. I checked my shop manual and found the
truck is already wired for DRL.I'm making an
assumption that this is because Canada requires DRL and
Ford does not want to have 2 wiring harnesses for the
same truck. So I checked my truck and sure enough,
the wiring harnesses are there and all I needed to do is
replace the loop-back
plug with the DRL Relay Block and install the DRL
Resistor into it's location.
Ford enables DRL on Canada trucks simply by plugging
in a DRL Relay Block and plugging in a DRL Resistor.
On American trucks without DRL, the wiring harness is
the same but they simply replace the DRL Relay Block
with a loop-back
plug and put a cap on the wiring harness where the
DRL Resistor plugs in. The loop-back
plug provides ground to the Multifunction Switch
(Steering Column High/Low/Flash to Pass switch) so the
lights still work when the DRL Relay Block is not
present. On trucks sold without DRL the DRL Relay
block is not present, so the resistor doesn't even need
to be plugged in... thus the cap. So for people
wanting to disable DRL on their trucks, all they need to
do is remove or unplug the resistor.
I want to
Disable DRL on my Truck...
This is actually very easy. You need to find
the resistor (See Location is Everything below)
and disconnect it. It's that easy. And
Yes... your low beam and high beams will still
work with the resistor unplugged. :)
I want to Enable
DRL for my Truck...
So you want DRL for your truck but don't want to go out
and get the electrical engineering degree needed to
install the Ford DRL "Kit"? Well... you can enable DRL for your truck without
hacking into your wiring harness. Use this site to
get locations and part numbers for doing this.
There is another good web site out there to help you
with this task. See the Other DRL Web
Site links below.
Location is
Everything!
Finding this stuff seems
to be the greatest challenge for everyone. Here is where everything is located on my truck.
DRL Resistor/Cap:
The DRL Resistor (or where it's supposed to be) is
located in the front of the truck. Click
for Diagrams
DRL Relay Block/DRL Loop-Back Plug:
The DRL Relay Block is located just under the top of the
passenger side dash. Click
for Diagrams
Part Numbers:
1999 and newer:
The part numbers depend on the year of truck you
have. What I have seen is that Below are the
part numbers of the Relay Block and the Resistor: (The
battery and penny give you an idea of size, click for a
larger picture)
Relay Block (Shown Left) - Ford Part Number
YL1Z-13B218-AA
Resistor (Shown Right) - Ford Part Number
XL3Z-14A601-AA
Cost of the relay block is about $45.00 and the resistor
is about $15.00. So for about $65.00 (including
shipping) you can plug in these parts and have DRL on
your truck. :)
1998 and older:
DRL Module - Ford Part Number F65Z-15A272-AA
Other DRL Web Sites!
I have received many emails about this and I'm not
surprised that other people have created web sites also. Here are those that I have seen:
http://www.geocities.com/skyjet1/DRL.html
Contacting Me!
You can email me at Storm@voicenet.com
if you have questions about this since I've done this on
my truck and it works like a champ.
Disclaimer:
(Sorry... I have to get legal for a minute)
What you do to your truck/car is your
business not mine. I am not responsible for damage
caused by you or someone else to you or your vehicle by
following any or all of these pages. Use at
your own risk! Work on your vehicle at your own
risk.
All the component location views and wiring
diagrams are from the 1999 F-150/250 Shop and Wiring
Diagram Manuals distributed by Helm
Incorporated. (I would recommend ANYONE
doing work on their vehicle to get the shop manual...
not cheap but they are good! You can even get them
on CD!)
The only numbers I found on the
plug were F4SB and 14489-P (Yellow Arrows) though the
connector number may be EPC34. If you can find the
plug I'm sure you can make your own loop-back plug.
:) (click for a larger picture)
The red arrows indicate the only 2
metal contacts in the loop-back plug which makes sense
since in the DRL
wiring diagram you can see that this would provide
ground to the Multifunction Switch (Steering Column
High/Low/Flash to Pass switch) when the DRL Relay block
in not installed. (click for a larger picture)
This is where the resistor is if
DRL is installed. If not you will just have a cap
on the wire harness. The blue arrow points to it's
location. (click for a larger picture)
If you lay on your back with your feet out the front
of the truck you can look under the left side and see
the wiring harness for the DRL Resistor (This photo is
taken from that view). The Blue arrow points
to the DRL Resistor (Cap shown on mine). The
Green arrow shows the wiring harness going to the left
headlamp. The Red arrow shows the wiring harness
going somewhere else (Never had the time to follow it).
The Yellow arrow shows the Fog Lamp harness. (click
for a larger picture)
My truck does not
have the Relay Block but it has the harness with the loop-back
plug. The blue arrow points to it's location. Note:
More info on how to access the wiring harness below the
diagram (click for a larger picture)
You can access the
wiring harness from the top of the dash. You will notice
an access panel that can easily be removed (Careful not
to mess up your dash)
After removing the
access panel, you can see where the DRL Relay block
would go: The Red arrow is showing the loop-back
plug. The Blue arrow is showing the RPO Relay Block.
The Yellow arrow is showing the the harness where the
Autolamp module goes (Not even going there!).
click for a larger picture
