Working on a little project that requires me to disbale my DRLs on my 2000. I did find instructions but they were a little unclear until it finally clicked in my head after bending backwards looking underneath the dash. So I decided to make it easier by posting a how-to with photos specifically showing where and what to do.
There's a relay block that contains two relays DIRECTLY behind the OBDII port. It has a cover and is held in by those plastic push clips.
Remove the plastic push clips. One on each side then it should just kinda fall down. There will be a cover that comes off easily to expose the two relays
The relay you want is towards the wiring harness coming out of the block. Just simply pull it out. To make it even easier if you're not sure which relay, turn your headlights on and they will turn back off when you pull the right relay.
Bend the 87 tab flat and simply plug it back in. Headlights will still work but your DRLs will never come on again!
t*ts! Thanks for this! I don't like DRLs becasue one could blow out during the daytime and you could get stopped by the fuzz when you didnt even 'need' to have your lights on to begin with!
Top post! Great job! Bravo - and thank you for posting this -- it may seem 'little' but it saves alot of time not having to hunt down stuff --- so I just want to say to you than YOU ARE APPRECIATED!
Don't do this if you are in Canada. The fuzz can get you with a $200 ticket for non functioning DRL. Happened to a friend a few weeks ago with a USA model 05 Grand Marquis that does not have DRL.
Now I know how to change the messed up relay in my Safari, thanks for the write up.
Don't do this if you are in Canada. The fuzz can get you with a $200 ticket for non functioning DRL. Happened to a friend a few weeks ago with a USA model 05 Grand Marquis that does not have DRL.
Now I know how to change the messed up relay in my Safari, thanks for the write up.
This isn't for Canada but I figured our Canadian members would know that :lol: . Make sure it is the relay. I think it's more common for the diode to go bad causing the DRL not to work. The best way to check a defective relay is to swap those two relays. They are identical. I think the other relay just keeps the radio and power windows on when you take out the key until you open the door.
Try checking this link out. viewtopic.php?f=76&t=11836 Seems like a little bit of work but you could do what one guy in that thread did which is cut out the diode entirely and splice the wires together. Then you'll have DRLs again. They'll just be full brightness but it'll be legal again.
Checked out that link about diode location, good to know. Still looking for the actual DRL module location to no avail. Sometimes when the van is started the DRL do not come on right away. There is sometimes a crackling sound coming from the under dash area during this. By then turning the headlights on and off the DRL will function again.
Try checking this link out. viewtopic.php?f=76&t=11836 Seems like a little bit of work but you could do what one guy in that thread did which is cut out the diode entirely and splice the wires together. Then you'll have DRLs again. They'll just be full brightness but it'll be legal again.
Didn't even splice the wires together - just stuck a bit of wire across the two pins on the connector, taped it in place, and put it all back together. 6 months later and all is well.
If a vehicle comes out of the factory with DRL and you disable them you CAN get a ticket ,,,,, There is a reason on why all cars today have them.. Disabling them is stupid , If you have em Use them...
If a vehicle comes out of the factory with DRL and you disable them you CAN get a ticket ,,,,, There is a reason on why all cars today have them.. Disabling them is stupid , If you have em Use them...
I disabled mine because I ran the headlights through my own relay with thicker wiring because I'm running 80 watt bulbs. The relay is triggered by the original headlight wiring. Now if I only have half the voltage coming through the original wiring because of the DRLs, the relay is probably gonna act erratically. We all know what they're for. It's not a big deal to me. All the vehicles I had before this one didn't even have DRLs. This thread isn't about if you should disable them. It's just for those who wish to. I'd be more worried about the people who do things like black out their headlights and taillights to the point that I can barely see them at night.
I can see it now , at high noon sun so bright you have to wear dark shades ,
then get pulled over by police and you ask the officer what did you do wrong? and he says , driving without your headlights on :rofl: :rofl: :rofl:
I can see it now , at high noon sun so bright you have to wear dark shades ,
then get pulled over by police and you ask the officer what did you do wrong? and he says , driving without your headlights on :rofl: :rofl: :rofl:
Can anyone tell me if this disables the DRL light on the dash as well? I just pulled the fuse for my DRL's, but the dash light still comes on. I'd like to disable it, if possible.
Can anyone tell me if this disables the DRL light on the dash as well? I just pulled the fuse for my DRL's, but the dash light still comes on. I'd like to disable it, if possible.
Working on a little project that requires me to disbale my DRLs on my 2000. I did find instructions but they were a little unclear until it finally clicked in my head after bending backwards looking underneath the dash. So I decided to make it easier by posting a how-to with photos specifically showing where and what to do.
There's a relay block that contains two relays DIRECTLY behind the OBDII port. It has a cover and is held in by those plastic push clips.
I tried this on my 2005 Astro and initially it seemed to work, but while out in the van a few weeks later, I noticed the headlights on in the daytime (the headlight switch was off). This was exactly what bending pin 87 was supposed to fix. I also noted other funny stuff happening, sometimes the 'brain' would decide that the headlights were on and dim the instrument lights, no big deal but it meant that the gear shift indicator and the clock/radio display effectively vanished. This was by no means consistent. Does anyone know if this mod just don't work on the 2005? And has anyone else tried it on a 2005 van?
Direct from the GM Techline eSI. Specific for a 2005 - other years probably do have some differences....
"The ambient light sensor is a light sensitive transistor that varies its voltage signal to the body control module (BCM) in response to changes to the outside (ambient) light level. When the BCM receives this signal it will either turn on the daytime running lamps (DRL) or the headlights for auto headlamp operation. Any function or condition that turns on the headlights will cancel the daytime running lamps operation. With the headlight switch in the OFF position, the headlights will either be turned ON or OFF, after an approximate 8 second delay depending on whether daylight or low light conditions are sensed. The DRL will operate when the ignition switch is in the RUN position, the gear selector is not in the PARK position and the parking brake is released. When these conditions have been met and the ambient light sensor indicates daytime conditions, the DRL will illuminate.
The DRL relay is supplied battery positive voltage by the GAUGES fuse in the IP fuse block. When the BCM requests DRL operation, the DRL relay coil is grounded by the BCM activating the relay. The energized DRL relay bypasses the multifunction headlamp dimmer switch by rerouting ground G110 directly to both low beam headlamp bulbs.
The automatic lamp control (ALC) system and the daytime running lamps (DRL) feature (except the Canadian version) can be temporarily disabled by performing the following procedure:
Turn the ignition to RUN.
Press the DOME OVERRIDE button four times within six seconds.
A chime will sound informing you that the system is off. The system will remain disabled until the ignition is cycled off and then on or by pressing the DOME OVERRIDE button four more times within six seconds. The chime will sound again signaling that the system has been reactivated.
The export vehicle is not equipped with the DRL feature."
On a 12v relay pins 85 and 86 are for the relay coil with 85 being negative and 86 positive. A relay can be activated with either positive or negative. The other 3 pins are for the feed (pin 30) and the relays switching states. With the relay not having its coil energized pin 30 is by default connected to pin 87a and when the relay coil is energized pin 30 connects to pin 87. So according to the GM Techline disabling pin 87 "should" effectively disable the DRL. You could essentially pull the relay and put a jumper in the socket across pins 30 and 87a and would have the same effect or jumpering pin 30 to 87 would force the DRL's to be on all the time (bad idea). My only thinking is maybe the BCM somehow monitors the DRL circuit or the DRL diode to verify that the DRL is functioning. The image is the official GM schematic for the 2005 DRL circuit. In the schematic I'm not 100% sure of the direction of the view on the schematic though (on the relay are you facing the relay or the socket?). Regardless the 2 state pins are 87 and 87a, according to the schematic disabling the wrong one would essentially disable your headlight switch by removing its ground when DRL is not active.. but the headlights might still work if the auto headlights feature is providing an alternate ground. Making my brain hurt - I'm going to look and see if my 2000 is different as I would like to disable the DRL's which is why I ended up in this thread to begin with. lol
Edit to add - if you are curious.... yes the 2000 DRL schematic is definitely different than the 2005. Realistically though it IS the same it just shows things in a different orientation but the pins are the same, even getting the same power for the coil and the same pin on the BCM to get the ground signal to activate the DRL's.
So after thinking on this for a few more after wrapping my head around this a little more I think disabling pin 87 or 87a is really not a good method to go about this. The problem is even though disabling pin 87 prevents the ground from switching to the DRL circuit (this does effectively disable DRL but.... the relay is also still disconnecting the ground from the headlight switch when the BCM activates the relay coil. Considering the BCM monitors all sorts of other functions it is very possible that this will have other unintended effects. I think the correct course of action would be to disconnect the relay coil by either bending pin 85 or 86 (would not matter which one really). I'm going to try this on my 2000 tomorrow and will post the results.
Why not do what I did; pop and bend that pin; then by the windshield vent there's your light detection whatever thingie... Take the grill off and pull just slightly on the little round point; believe it's windshield right area. It will come out and about 1 - 2 inches down will have a connector. Disconnect top from wire.
Bend it so that one end goes into plug pin 1 and the. Bend the other so the other end goes into connector pin 2.
That's it; put everything back together and now your van thinks we never have night time. Make sure neither end is touching together. Works like a charm for me!
Why not do what I did; pop and bend that pin; then by the windshield vent there's your light detection whatever thingie... Take the grill off and pull just slightly on the little round point; believe it's windshield right area. It will come out and about 1 - 2 inches down will have a connector. Disconnect top from wire.
Bend it so that one end goes into plug pin 1 and the. Bend the other so the other end goes into connector pin 2.
That's it; put everything back together and now your van thinks we never have night time. Make sure neither end is touching together. Works like a charm for me!
I tried this (bending pin 87) on my 2005 Astro and initially it seemed to work, but while out in the van a few weeks later, I noticed the headlights on in the daytime (the headlight switch was off). This was exactly what bending pin 87 was supposed to fix. I also noted other funny stuff happening, sometimes the 'brain' would decide that the headlights were on and dim the instrument lights, no big deal but it meant that the gear shift indicator and the clock/radio display effectively vanished. This was by no means consistent. Does anyone know if this mod just don't work on the 2005? And has anyone else tried it on a 2005 van?
Actually if it works by just killing the relay coil it is just disconnecting one wire and a very simple procedure other than it does require you to contort yourself to reach the relay under the dash. Now for me, I do like the automatic headlights so I've not looked into disabling the light sensor.
That being said logic tells me that killing the negative or positive trigger to the relay coil will work perfect and that the BCM will think that it the DRL is still functioning just as it should there is still a possibility that it might not be quite so simple. For example if the BCM says "okay it is bright outside, I'm going to activate the DRL's" and it dutifully grounds the DRL relay coil, and then the BCM somehow monitors the voltage draw on the headlight circuit to verify that the headlights are on. If that is the case then it might not work or again have unintended side effects. Without literally spending hours upon hours of pulling up every schematic for the van and studying them or knowing exactly what the BCM programming does and does not monitor the only way to really be sure is to test it with a bit of trial and error.
It might very well be simple, hopefully so. However it might not.... Reading a bit further in the GM eSI system (this is on a 2000 model) I am finding the following though. One - the ambient light sensor is for both the DRL and auto headlight functions. The BCM does monitor the light sensor.
"The body control module (BCM) monitors CKT 278 in order to determine if the daytime running lights (DRL) or the auto headlights (AHL) should be turned ON in the AUTO mode. When the BCM senses the ambient light sensor voltage between 1.7 4.7 volts (light state) the DRL will be commanded ON. When the BCM senses the ambient light sensor voltage between 0.2 1.0 volts (dark state) the AHL will be commanded ON."
So the BCM expects to see something form the sensor at all times. The sensor uses a 5v reference and it will trigger a DTC (diagnostic trouble code) on the BCM is the monitored voltage drops below .2 volts. So you could use a resistor and bypass the sensor to lock it to a specific voltage. If you put a large enough value resistor to drop the voltage to the range indicated above. This will of course affect both DRL and automatic headlights. For a headlight circuit, due to the extra features of DRL and automatic lighting it is surprisingly complex with a lot of interactions and monitoring for problems which does make a a bit more complex to wrap your head around it and figure out exactly how it works and what happens when certain things are done. In the end though once it is figured out the actual modification should be very simple.
Regardless of all of that I'm going to give it a try but it might take me a day or two to report back on if it works as expected. I think it will though.
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