This is how I kept DRL with an HID system on a 03 Cavalier. The method I've used doesn't require any modification to the vehicle wiring except replacing the DRL shunt.
Material :
2X DC relay ( I've use two 12V 10A relay with 400 Ohm coil resistance)
2X 1N4001 ( diode for back-emf protection)
1X 5 or 10W resistor (39ohm in my case)
5 watt is still overkill but those resistor are easy to mount on the frame.
Well the idea is simple, I've replaced the original 0.3 Ohm shunt with a 39 Ohm resistor and two relay provide the necessary load to mimic the original system.
This way the BCM think the two bulb are working and so wont flash the headlight.
The new shunt resistor must be chosen carefully, it depend on the resistance of the two relay you use. Bosch relay could be used but they have a low resistance (75 Ohm) and will cause the shunt to dissipate more heat. Using 2 bosch relay, the shunt will dissipate 0,6 watt.
To find out what shunt you need, use this formula : Rshunt = 0,1 X Rrelay (use only the resistance of one relay)
This is a quick draw of what I've done with the relay (on each hid ballast) :
I've installed the relay on the wiring that come with the HID system, so no need to cut any wire on the car.
With this method the ballast will see a full 12,6 V in DRL mode.
Nice but wouldnt this be better in the exterior forum?
TheSundownFire wrote:Nice but wouldnt this be better in the exterior forum?
its still electronics......
click sig for my car audio videos
I mean it goes with the DRL and other headlight tricks sticky.
Actually, I think it could be both imo. After all, it deals with electronics and exterior (headlights) in one boat.
i know this is an old thread... but this how-to seems incomplete...
i see where the relays and the diode go, what about the resistors? and where is the DRL Shunt?
Jeffie?? Brian??
Edited 1 time(s). Last edited Sunday, March 21, 2010 7:54 AM
Hi Kyle, it looks like the shunt goes in between the positive and the low beam wire. He also has the diode going to the low beams as well. The resistor will only be needed on the passenger side? I think that's the side that DRLs look for a working bulb.
Your car may do 13 sec @ 103 mph, but my car does 146db @ 35 hz.
WTF do I know about wiring headlights?
yeah Jeffie said that the common hot on the 00+ wiring is getting foobarred by the hid relay resistance vs actual hallogen resistance...
so i can try 95 - 99 headlight harness which will keep the high beams on their own circuit or i could try the DRL disable trick, but ground out the other side which will keep the DRLs running all the time, but run a relay with the headlight switch with ignition only power to control it with headlight on and off
The 95-99 harness runs two hots, then a negative for low and one for high. Sunfires ran a common hot too. That's where the resistor comes into play. HIDs should have less resistance than a halogen bulb.
Your car may do 13 sec @ 103 mph, but my car does 146db @ 35 hz.
