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!
