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2007 Daytime Running Lights

floridawheels

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Is there a relatively easy way to disable the DRLs WITHOUT affecting anything else?

My thoughts would be possibly pull a fuse or relay or find the switch that senses when you have the (air) parking brake set and pull the wire.

I think pulling the parking brake switch wire would leave the dash "Brake" light on all the time, not acceptable.

So, any advise?

Please note: This is NOT a discussion of why or why not to disable/bypass the DRL. I have a specific reason/need. (Completely legal and 100% not nefarious reason). This is a conversation on how to best go about doing it.... Thanks...
 

Hino123

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Thats kind of an odd request for me, usually people want them fixed not disabled. Either way I looked into it a little. That is an extremly busy circuit. The DRL has many inputs/outputs/circuit protection devises and a few diodes. Just exactly how the circuit is configured will depend on how the truck is built and various options. Air suspension, air/hyd brakes etc.
Without knowing your exact options I would just start by removing the 5a DRL fuse, then try the DRL relay. Be sure to check all your ights after. I have attached a location for the DRL relay, DRL module and a napkin drawing of the the circuit. Let us know how you make out.
 

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Hino123

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Just an FYI, In DRL mode there is only 9volts supplied to the low beams via a PWM signal. Yet in regular low beam mode there is full batt voltage suppled to the low beams.
 
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floridawheels

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Just an FYI, In DRL mode there is only 9volts supplied to the low beams via a PWM signal. Yet in regular low beam mode there is full batt voltage suppled to the low beams.
Bingo... THAT'S exactly the problem. At least I THINK it is...

I buff/polish/renew the headlight lenses every 8-12 months to keep them as clear as possible. I also have high quality brand name bulbs of legal DOT approved wattage. Yet the light on road always seems dim and the heat generated by the bulbs keeps melting the plugs on the wire harness.

I have replaced the plugs 3-4x (with quality replacement parts, using 3AM brand marine crimp/heat shrink terminals)

I found a set of LED bulbs and tried them. #1 They have a Short pigtail wire for the plug that moves it away from the heat so now the plugs have quit melting.

#2 Holy cow are they bright! I never get flashed by oncoming traffic so they don't seem to be a problem but from the driver seat.. Man what a difference!

Anyway, I figured the DRL worked by sending reduced voltage to the lights (but was to lazy to actually measure it) and I was initially concerned that the (assumed) lower voltage would not let the LEDs work but it did... For awhile.

After about 2 months the low beams have gone nuts. They work about 50% brightness 80% of the time, full bright the rest. When on "dim" they have an erratic "strobe like" action so now driving at night is like being in a disco.

The bulbs are covered by warranty, so no problem there but I don't want to kill the new ones.

I'll try your ideas and let you know how it goes. Will be a day or two before I'm back with the truck, (I'm on "another assignment" now...Lol)

And THANKS, for the time and info!
 

floridawheels

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Truck running, parking brake off, DRLs on, Headlight switch off
Removed the DRL fuse: DRLs remain on. - operated the normal headlight switch, no change. (Didn't expect any)
Replaced fuse.

Removed the fuse directly above the DRL fuse. It is marked "Headlight dim relay" - low beams/DRL out. lights do not work with normal switch.
Fuse replaced, everything functions normally.

Removed both of the above noted fuses (DRL/low beam off) and replaced only the headlight dim relay fuse. both DRL and normal low beams remain off and the normal switch does not work. Replaced DRL fuse, normal function returns.

Set parking brake on (DRL off). Removed DRL fuse (DRL remain off). Parking brake off (DRL fuse still out) DRL ON.!

Done with fuses, moved onto the DRL relay; Removed DRL relay, both DRL off and NO normal low beams.

Learned:
Removing the DRL fuse once the DRL is on has no effect.
Removing low beam relay fuse kills everything
Removing both fuses and replacing the relay fuse nothing works. replacing the DRL fuse returns normal function.
Removing the DRL relay kills both the DRL and normal low beams.
Confused by results of last test with parking brake and fuse. Not sure how the DRL comes on with the fuse out?

Obviously they never intended for the DRL to be easily disabled. You would think they would have installed a switch like many normal cars have to be able to simply turn the DRL off.

I sent you the VIN in a PM. I assume that will give you the info you need to know what/how the truck was equipped?
 
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Hino123

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Ill have to look at the schematic tomorrow, i spent a little time looking at the napkin drawing I attached but its missing quite a bit of data. . You may end up removing a wire from the DRL module. Ill let you know what I come up with.
 
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floridawheels

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Ill have to look at the schematic tomorrow, i spent a little time looking at the napkin drawing I attached but its missing quite a bit of data. . You may end up removing a wire from the DRL module. Ill let you know what I come up with.
Wire surgery.. no problem. Assuming that works as expected if I ever go back to regular bulbs I could put a switch in that line to have or not have DRL as wanted.

And thanks for confirming what I was thinking about the wire drawing. I looked at it but decided there was more info needed to make it truly useful.

If I need to operate on the DRL module, where in the truck is that ECU rack located?

Thanks!
 
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Hino123

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Yeah a switch inline might be a good idea if you need to re-enable them. The ecu rack is essentially behind the pass side fuse/relay center where you were pulling fuses and relays. The DRL module is on the top rh above the fuses. You will need to remove the rh speaker cover, the top and rh side panels surrounding the fuse relay center. PM me a good email address, and when i get the correct schematic I can forward it to you.
 
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floridawheels

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Oh boy, that sounds like fun...
I'll look at that and also maybe following the wire to where it goes and intercept it on its way if access is easier.

Email address sent!

THANK YOU
 

natsys

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Did you ever figure this one out? I wanted to switch to LED's but had the same questions about how they would work with the DRL's.

Keep us posted.
 

floridawheels

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Yes, sure did. Been meaning to post how I did it. It's pretty simple but requires some basic wiring. Later tonight when I have more time I'll write it up and post it.
 
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floridawheels

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The solution:

After determining that Hino did just about everything they could to insure that you always had your DRLs on when driving and that in DRL mode your LED bulbs won't last long I have come up with with 2 solutions.

Plan #1) This one is a pain and almost certian not to be a viable solution for most people. It is a 2 step fully manual system. And requires no wiring modifications at all.
Step #1) Make sure that EVERYTIME you release the parking brake you first manually turn on the normal headlights in low beam.

Step #2) EVERYTIME you set the parking brake shut off the headlights.

Plan #2 is a much more user friendly approach as it is completely automatic but it does require some basic wiring skills and about an hour or so to do.

You'll need some wire, I used 8ga. It's overkill but I ALWAYS go heavy with my wire size and I NEVER have low voltage/amperage issues. You'll also need some 10ga wire, 2 30amp "Bosch" square relays and bases, 3 in line fuse holders, 1 fuse 30a, 2 fuses 10a. Assorted WEATHERPROOF butt splice connectors, correctly sized split loom to cover all your new wiring and the tools/knowledge how to use them.

There are some shortcuts you can make and some parts you can skip. However, this is a critical system on the vehicle and I would not consider anything less that a professional quality job as being acceptable.

Open the hood, remove the inner fender covers to access the headlights and identify the low beam wire for each (left and right side). These wires are individually fused by the factory to insure that if one side shorts out the other side still works. This modification, when done without shortcuts does the same thing.

If your headlight plugs are all melted now would be a good time to replace them. Cheap plugs are available at any auto parts store and if your new LED bulbs have a pigtail on them to keep the plug from direct contact with the bulb the cheap plugs should be fine. Good high quality plugs can be ordered online.

Cut the low beam wire leaving at least 2" of wire on the plug to work with. KkkStrip both ends of the wire and crimp on a butt connector to each end.
Kkkk
Pull the cover off your batteries. Attach 1 end of a fuse holder (leave the fuse out for now) to the positive post of any battery. Splice into the other end your 8ga wire. Run the 8ga wire up to the left headlight making sure you accommodate for the hood tilt, keep away from hot or moving parts.

Run a price of 10ga from the left light to the right light. Alternatively, you could use 10ga to go from the battery using a sepperate wire to go battery to each headlight.

Assuming you used a single 8ga for your power at the left light you will have the 8ga power from the battery and the 10ga jumper to the right light. At the left headlight area connect them together on the same side of a butt connector.

Now to the bases with pigtails for your Bosch type relays..
Attach a fuse holder to the wire for pin 87
Attach the other end of the fuse holder to your 8 or 10ga power wire
Attach the wire for pin 30 to the low beam plug, (where you left at least 2" of wire to work with)
Wire for relay pin 85 goes to the d power wire for the low beams, (the "truck side" of the wire you cut at the beginning.
Wire for relay pin 86 goes to a good ground.

Now cover EVERY wire with split loom and make sure ALL your wire connections are clean, tight and waterproof.

Install your fuses. The big one at the battery and the other 2 right there at the headlights.

Test the system. See the below explication of how it should function to be sure it does in fact work as planned.

Assuming the system tested good, replace the inner fender light covers and close the hood.

Ok, so why did we do all that and how does it now work?

First a few facts for you to digest. The factory feeds 9 volts to the normal bulbs in DRL mode. It is this 9 volts that kills the LEDs. They work for a month or so but long term they can't tolerate the constant low voltage and they puke.

In normal low beam use (manual switch on) the truck feeds a full 12,volts to the bulbs.

All we have done is insert a relay that anytime it sees either 9 or 12 volts at its control will activate and send a full 12 volts to the bulb low beam element.

We have provided fuse protection for our supply at the battery.
We have provided individual left and right fuse protection at each light maintaining factory level circuit protection and isolation.

Now anytime you release the park brake the relay sees 9 volts and activates thereby sending 12 volts to the bulbs so your DRLs are actually full strength light now.

Anytime you operate the manual switch the relay sees 12 volts instead of 9 which is no problem for the relay and it passes on 12 volts.

To test: manually turn on lights with the normal switch. Both low beams should come on as always. Go on and test the high beams but we did nothing to that circuit so if they done work you have a sepperate problem.. or you didn't follow instructions properly.

Turn off the lights. Carefully chock at least 2 wheels or have someone hold the foot brake. Start the engine and release the parking brake. The DRLs should come on represented by both low beams coming on at full strength. Set the parking brake, DRLs go out.

Release the brake (DRLs on) and turn switch on. You should see no change. Set parking brake. Low beams remain on just as before. Turn manual light switch off, lights off.

The system is completely automatic and requires zero new or, different that normal, input from the driver. Zero driver training is required. Zero change in driver habit required.

Total cost, not including the new LED bulbs is about $20-40 and total time is about 1-2 hours. I had spare parts and stuff left over from previous projects everything I ne fed so I didn't have to buy anything but the LED bulbs and I went slow and made my wire runs look factory so it took me about 90 minutes.


Hope this helps.. good luck!
 
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Hino123

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Very nice, I'm glad you were able to get it to work. I have never had a customer ask me to dis-able them, but now I at the very least say it can be done!
 

floridawheels

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Very nice, I'm glad you were able to get it to work. I have never had a customer ask me to dis-able them, but now I at the very least say it can be done!
Yeah, me too! LOL.

Technically speaking I didn't disable the DRLs which was my initial plan, (again not because I have anything against DRLs, in fact I actually like having them, but the 9 volts issue was killing the LED bulbs)

It's more like I "Alternatively abled" them.

Thinking about it though if for some reason DRLs were a problem for you, installing another Bosch 30a relay in your new power wire and using the parking lights as the trigger for that relay would keep the low beams off all the time except for when the parking lights were on and the parking brake was released.

If you wanted the DRLs off even when the parking lights were on, then you add a manual switch to control the additional relay instead of using the parking lights as the trigger. Of course now you would have to manually enable that switch every evening in order for the low beams to work as normal (or at all for that matter)!

I have seen several cars that have a factory installed "DRL off" switch. Had Hino seen fit to give the driver the same consideration this entire thread would not have been necessary.
 

greasytshirt

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I'm glad you got it to work the way you liked.


Remember that brake switch harness break you suffered? I finally had one come in doing the same thing. It took about two hours to find the break.

Sent from my XT1585 using EO Forums mobile app
 

floridawheels

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They, (frame shop) did an outstanding job!

Honestly, it rides better now than before!

Entire rear suspension was replaced. All driveshafts trued, balanced, all new U joints and hangers.

2 new rear wheels, 4 new rear tires (and I replaced the front rubber at same time).
 
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