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Theory freak learning...
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Discussion Starter #1 (Edited)
Hi all!

I was thinking about it long time ago but I finally manage to do it last Saturday... I disabled my daytime headlight! So I hope you will enjoy my little HOW-TO write-up.

History
Well since 1989, every vehicles sold in Canada should be equipped with daytime running lights for security purpose. This mean that at least a pair of front lights should ALWAYS BE ON (intensity may vary from full light). You can find more info on that law here: http://www.tc.gc.ca/en/faq/road.htm#daytime running lights.

Why to do it?!
Well, U.S. model don't have it, so why mine should? Also, with the headlights always on, they will burn out earlier and I want to take care of my PIAA ;). And finally, the look is so cool without it. Plus, I really don't think any cops will bother me with that. If so, the surgery is reversible easily!

The Basics
So, how it works? Simple. Every Canadian B15 (and probaly every Nissan) headlight wiring pass by a module call the Daytime Light Control Unit (DLCU). This module controls every aspect of the headlight including daytime light, low beam, high beam, car park, etc). The daytime light only work when every others lights are off. Once you turn on parking light, low or high, they will "turn off". The daytime light are actually the high beam headlight wired in series, thus operating at half illumination.

This idea came to me because when the parking brake is apply (pull) before to start the car, the daytime light WON'T turn on. So, the easiest way to disable the daytime light are to fake the DLCU by let him think the parking brake is always apply. That way, headlight will work as usual without the daytime light when everything else is off. Also, after the mod, your "brake" cluster warning light will still be fully functional and operate as normal.

Part needed:
  • Only 1' of 16~18 gauge size wire (can be done even without it)
Tools needed:
  • Screwdriver set
  • Wire skinner/cutter
  • Electrical tape
Time required: 30 minutes

Skill: Easy

How-to step-by-step:
  1. Remove key from ignition (if so)
  2. Open the driver's door
  3. Apply (pull) parking hand brake
  4. Locate and remove the plastic screw-nut on the lower left dash garnish panel
  5. Pull the lower side garnish a bit to free up the other one
  6. Remove the plastic garnish
  7. You now have access to the DLCU (the black plastic box)
  8. Unscrew the metal harness
  9. Locate the light green wire. This wire goes (not directly) to the parking brake switch. When brake is apply, ground (0V) is on that wire; when parking brake release, battery voltage (+12V) is on that wire.
  10. Cut and skin it
  11. Isolate with electrical tape the wire coming from the hand brake switch
  12. Tie and tape the 1' spare wire to the connector side wire
  13. Skin long enough the spare wire and wind around the harness screw. This will fake the DLCU by always sending a ground signal and thinking the parking brake is applied.
  14. Plug back the connector
  15. Screw back the harness with carefully being sure wire is under the bolt
  16. Test your setup
  17. Put back the plastic garnish
  18. You're done!
So, what do you think? Real cheap mod no? :D

Open to any comments and enjoy!

***UPDATE*** Check down the thread with my switch added to the mod or click here:
http://www.b15sentra.net/forums/showthread.php?s=&postid=383800#post390770
 

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Cool

Just a few questions..

1. Does your parking brake light stay on continuously?

2. How do i wire it so the headlights automatically turn off when I turn off the car (with the headlight switch still on the 'on' position)? This is kind of opposite of what you did in the first place!
 

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Bow to your SE GOD
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In that case, I'd wire my headlights through a relay, so that whenever the car is on, the low beams are on. That is the easiest way I can think, to have the lights shut off automatically when the car is turned off. I'm not sure if you'd have to rig up a bypass for that stupid little reminder chime, though.
I'm going to do the dyatime light mod this week. I drive with my lights on every time I drive anyway, and I HATE how yellow my PIAAs look on daytime mode.
 

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Cool but...

The 50 years old mother of my best friend got a 1994 Sentra GXE (beige color, common's old women car! hahaha) and her daylights stop running by itself. Only 2 WEEKS after she notice than her daylights are dead, she get an HEAVY ticket from the police and she asn't driving too fast, she's be stopped by the cops ONLY about the D.R.L.. Hummm as I remember, it's around 150$ CDN for having the D.R.L. not fonctionning on a car who's factory equiped of it.

So, think about this............ cheap mod for sure, but HEAVY ticket for sure too : BAD.


SimmZ
 

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If the cops see that your day time running light are not working, they can give you a ticket! all cars sold in canada must have "working" daytime running lights! Most cops wont bother you, but you might just fall on a cop that has nothing better to do! Hopefuly you'll just get a warning!
 

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Theory freak learning...
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Discussion Starter #6 (Edited)
szwliew said:
Cool

Just a few questions..

1. Does your parking brake light stay on continuously?

2. How do i wire it so the headlights automatically turn off when I turn off the car (with the headlight switch still on the 'on' position)? This is kind of opposite of what you did in the first place!
1. As I said in the post, your "brake" cluster warning light will still be fully functional and operate as normal. That mean it will light up only when the hand brake is pulled.
2. Why would you like to do it??? I love to be able turning on my headlight without key in ignition... but I will check that if I got time...

SimmZ: I just CAN'T beleive it man! Why they did'nt give her at least a 48h warning or something... man that's bad. One thing I don't get is I saw lot of U.S. car license in Quebec (or Canada) and they did'nt have any daytime light...

So I think I will modified my setup and add a switch to turn them on... Or I may turn on my shitty yellowish fog light everytime... I think about it.
 

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Captain Underpants
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Woohoo!

Thanks for the write up! I appreciate you taking the time to make the How-To. Where did you find the wiring information?

I think that I'm gonna do this mod and use a switch to enable/disable my DRL.
 

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A car have to be approved by the laws of the country/province it was PLATED, not by the place it was driven...

Actually a car plated with a Quebec's license need to have daylights. The law it's the law :(


SimmZ
 

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angel2167882 said:

2. Why would you like to do it??? I love to be able turning on my headlight without key in ignition... but I will check that if I got time...
1st car: I left the headlights on a few times and killed the battery. Wasted a lot of my time!

2nd car: lights turned off with ignition, so that spoiled me...

3rd car: Since I have a habit of leaving hte lights on, I want to make sure I don't drain the battery!

I wouldn't mind doing the DRL mod...I find it hard to believe a cop would pull you over for it unless you were doing something stupid. And DRL's aren't really noticible unless its dark enough when you should have your lights on. But who knows, it happened once already.
 

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SimmZ said:

So, think about this............ cheap mod for sure, but HEAVY ticket for sure too : BAD.
Not only the ticket but a car without DRLs will fail inspection. Meaning if you try and sell it you will have to reverse the mod. Also the fine for 150 is just for none functioning saftey equipment. If they find out you did it on purpose. Watch out !! I was worried about burnning out my PIAA's early on my Integra with DRLs. But 4 years later and they were working strong.
 

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Discussion Starter #11 (Edited)
Re: Woohoo!

Spec V Boi said:
Where did you find the wiring information?
I think that I'm gonna do this mod and use a switch to enable/disable my DRL.
Well, you may not believe me but the dealer's guy at the parts gave me the wiring diagram :p After all, it's MY car and they don't care about what I do... but they all know that I should be aware of warranty void if there is a problem...

I have scan the diagram but this is the only page I have... it miss lot of other info on the module. He gave me only the part with the parking brake terminal. Ok so here it is (sorry, it's big for reading quality purpose):

Hope this help! I keep you in touch about my future switch add...
 

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It might be easier to pull the light green wire from the plug and jumper the black wire (#9) to the place where the green wire was. That way you would not have to cut anything and you would not actually have to ground the terminal to the shell of the device. Just remember to tape up the green wire you pulled out or else you risk shorting the battery voltage 12V to ground and you could melt your wires if it is not fused or blow the fuse if it is. But remember to do that in both cases (very important)
 

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Also there is the inspection, too, that you wouldnt pass... if y'all do that... i'm not well versed in Canadian laws (this is the first i heard of the DTRL law).

How do the DTRL work? The low beams are forced on at ALL times? or just during certain times of the day? or is it just the parking lights that stay on?

this has got me curious... I also am striving toward my 2000th post........ :D
 

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Alex said:
Also there is the inspection, too, that you wouldnt pass... if y'all do that... i'm not well versed in Canadian laws (this is the first i heard of the DTRL law).

How do the DTRL work? The low beams are forced on at ALL times? or just during certain times of the day? or is it just the parking lights that stay on?

this has got me curious... I also am striving toward my 2000th post........ :D
DRL's work by turning on your high beams at a very low wattage when you start your car. I think they set the high beams at about 40% of their normal wattage. In Canada we are just starting to get yearly inspections, but they are mostly for emissions testing. Though in Ottawa they have had several surprise roadside saftey inspection.
 

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Bow to your SE GOD
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We have nothing for inspections, except the 10 year old+, and out-of-province inspections.
I wish we did, though. There are some real pieces of crap on the road.
If you do this mod, you just have to turn your lights on every time you drive. No prob.

Angel: Do you still get the warning chime if you've left your lights on, and you open your door?
TIA
 

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Discussion Starter #16
Alex said:
Also there is the inspection, too, that you wouldnt pass... if y'all do that... i'm not well versed in Canadian laws (this is the first i heard of the DTRL law).

How do the DTRL work? The low beams are forced on at ALL times? or just during certain times of the day? or is it just the parking lights that stay on?

this has got me curious... I also am striving toward my 2000th post........ :D
Uno, about the inspection, there is no one here in Quebec until the car is came back on road after a "official" store (for winter or so), damage and rebuild, 10 yr old car, un-licensed and re-licensed or if a cop catch you and told you to pass one. Otherwise, any casual car driven have no inspection at all.
Secondo, as for the DTRL (on the B15), as I said in the How-to (The Basics section), The daytime light are actually the high beam headlight wired in series, thus operating at half illumination;)... And i'm sure about that. As for other car, I don't know but it should be about the same. I'm not flaming you, don't worry :p


audio1der said:
Angel: Do you still get the warning chime if you've left your lights on, and you open your door?
TIA
Have just check, warning chime is working as usual...even with parking brake pull. So the mod don't affect it at all.


As other users try to sensitize me to be an "illegal" mod and being catch by a mad cop, you convince me to add a switch to my mod. That way, I will be able to turn on DTRL anytime. I'm on my way to do it and I will post an update with pics in couple of hours:)

Cya!
 

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Captain Underpants
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I did the DRL mod yesterday and installed a switch as well. It's too bad that the we're trying to provide a ground path and not +12V because the switch that I bought can't light up...oh well. One thing that messed me up when I was testing the mod was the fact that once the DRL have been enabled (open circuit), it can't be disabled again...so I thought that I messed up the mod until I remembered that when you pull your parking brake the DRL stay on until the next time you start your car.

I also did the foglight rewire, so now I can full control of my lighting. I can drive with parking lights and fogs on (no headlights) or even have my fogs on when my highbeams are on too.

It's a cheap mod, just takes a little time and patience.
 

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Discussion Starter #20 (Edited)
Switch Update!!!

Ok so I finally wire a switch to the mod and it's great. At least now, the mod is totally reversible with simply a touch of a button :p (good for aware cops)

As for the switch itself, let me just tell you that you need a "ON-ON", 3 pin switch. This is because if the light green wire is not grounded anymore, it need to make a contact with the original cable. If you use a regular 2 pin switch, the signal going into the DCLU will be "floating" and this is no good in electricity. Let me explain it in details...

Wiring with switch specs:
  • Switch to OFF: Contact is made with the ground screw and the light green wire going into the DCLU (like the original mod)
  • Switch to ON: Contact is made with the light green wire end-to-end (like the factory setup)
Hope you understand... if not, don't worry, I have enclose pics just below :D

Switch and hole cut into the garnish:


Switch wiring with the actual mod:


Final result (2 pics):



Oh and last thing... once you turn on the switch while the car is running, the day light WON'T come off if the switch is turn back off after (until engine is turn off again). This is exactly like how it work with the hand brake on the stock setup.

Now I think my mod is complete :cool:
 
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