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Headlight switch issues related to melted HDM relay?

W

wytnoyz

New member
We own a 2008 Grand Prix GXP that developed an issue a while back with the headlights where they would switch to high beam while turning a corner. While this is great for the driver's ability to see the corner, it's not so great for oncoming traffic. We've adjusted to the problem by holding the turn signal lever, jiggling the lever, hand canceling the turn signal. I figured once the holidays were over I'd order the switch and be done with the problem.

Cut to a couple of days ago. My wife comes home Tuesday morning from running errands, parks in the garage and goes on about her day. Ten or so minutes later, my son mentions he smells something burning, like an electrical fire? Smell gets stronger near the door to the garage so they go out to find the garage filling with a strong acrid smoke smelling like burning plastic coming from the front of the car. They call me at work, I tell them get the car outside asap. I had them check the hood before opening it to find the fuse box smoking. They took off the cover and the relay marked HDM that controls the low beams and drl's had melted into the fuse block. Luckily she wasn't on the interstate or somewhere she couldn't stop. I've since read of similar cases resulting in the car burning to the ground. So now I'm not only replacing the switch but also the fuse block. Yay! $$$$

i didn't see any other posts related to similar issues, but I can't help but think the two are related and probably not unique to Grand Prix. Any thoughts?
 
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The HDM module is a common failure on the 04+ cars.

I guess yours just failed to the extreme and caused the fuse block to melt. Kinda sucks to have to replace both.
 
About the only good thing about this was I found both parts at a good price at iamgmparts.com. They sell only new gm parts but way less than what a dealer would want.
 
*Update to post* We tried to order the parts I needed to fix the problems I described only to find the fuse panel is on National Backorder till who knows when. This makes me wonder is this caused by demand for this panel due to the ongoing issues with relays and panels melting and burning or what.. One parts supplier mentioned even though GM has to carry replacement parts for 10 years after the model year, they could just decide to stop producing this part and leave the back order in place for another 4 years, a basically ignoring the problem.
 
We did finally find a used one in Kansas using a parts locator website. Turns out it was one of only three available nationwide which again makes me wonder why they're in such short supply considering they're used in other W bodies besides Grand Prix. It doesn't leave much of an option for anyone that's having the same issues. GM should have issued a recall based on a known problem or at least produced more of the fuse panels in advance of the demand.
 


I don't know if they've revised/updated the design. I've seen some posts where people replaced relays 4-5 times only to have them fail again, no way to tell if they replaced with oem or aftermarket parts. For some like myself, it seems to be related to the headlight/turn signal issue showing up and usually it's in a high mileage vehicle.
 
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