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No low beams (03 Grand Prix)

F

Fahrenheit

New member
So the bulbs are known good (I checked them in another car). High beams and all other lights work. Low beams do not. I can't find a good wiring diagram for the car to chase this issue down. If it was just a bad switch wouldn't the auto sensor still kick on the headlights when it detected low light? Anything else I should check out before I give up and let a shop look at it?
 


I can confirm voltage and wire integrity up till the wire go into the firewall. Where is the Daytime running lamps control module?
 
Yeah, figured it out. Luckily I found it with a magnet. I'm gonna finish up the front control arms/struts and I think i'm just gonna let a shop handle the headlight issue.
 
Fahrenheit said:
Where is the Daytime running lamps control module?
Click to expand...
Open the drivers door and remove the plastic cover on the side of the dash....

DRL_Heatsink.JPG
 


So I got time to work on it today and I pulled the module? I checked the resistance on it and get 8.85 ohms. It is slowly counting down if I leave the leads on it. Also it looks like if I just unplug it the head lights should work with the switch. They do not so i'm gonna assume that's not my issue. I'm kinda stumped. What leads do I need to check for voltage when testing the head light switch? I do not get voltage to the diode. The thing before the diode is the head light switch.
 
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So I got the new DRL module, they are not the same but maybe it was just a revision?
CHDlFEm.jpg


It didn't fix the issue. So I did some more experimenting since I had 2 DRL modules, here's what I did
ofrKC4Q.jpg


So I have low beams with these pins jumped and everything works fine, the only thing that does't work right when doing it like this is when I click on high beams. With high beams on both filaments of the 9007 bulb light up. I think if I leave the high beams on to long the bulb will burn out and or melt the head light housing though with my googling it seem's a lot of dodge truck guys mod thier trucks to have both filaments on and have no real issues. Though they are dodge guys, what do they know? So what i'm doing here is jumping the 12volt power from the headlight switch (yellow wire) right to the dark blue of the low beam output.

I'm still not sure what the issue is. I'm total lost since it seems like every test I did pointed towards the DRL module being bad but it seem's like that is not the case
 
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