Headlight ground corroded out - DIY Replacement

JHZR2

Staff member
Joined
Dec 14, 2002
Messages
47,052
Location
New Jersey
One of the headlights on my 04 Saab 9-3 was out. Turned out it wasnt the bulb, but rather the ground connection on the socket had corroded for whatever reason... I think it is because there is added stress and heat, due to the ground being two wires twisted together (daisy chain for the turn signal), versus one for the positive. I ended up buying some ceramic H7 bulb sockets from Amazon, and I had some butt splices which have a bit of solder inside and shrinkwrap on the outside - perfect for combining something like this. Standard Del City fare. H7 Socket The OE connector is made of two parts which snap into one another. The bulb socket proper, and the outer ring which is the interface to the glass reflector. They can be removed, and then the outer ring, which will be reused, can be adapted. Here it is with the snap connection removed. The two holes in the ring are for two index pins on the connector. They dont have any use. I just filed the bumps around them flat enough to tightly accommodate the new connector. I was thinking of holding it in place with silicone, which has a bit of give, but I didnt find the right stuff with heat resistance, so I went with Epoxy. I got 180 degree rated stuff, perhaps there is a higher temperature version which would be prudent. I installed the pieces together and included the bulb. This was important to ensure that the spacing and depth was correct between the ring and where the bulb must sit, and also to ensure that alignment is right. I applied the epoxy, taking care to do it so that gravity would help the path and I wouldnt epoxy the bulb into the socket... Five minute epoxy is great since it sets quick, so you can get the outside done and then reinforce by adding epoxy to the inside. Let it cure a bit, and then put it into service! In this weather, the heat from the bulb probably helps speed the cure... Good luck!
 
Joined
Mar 24, 2007
Messages
10,008
Location
Upstate NY
Good work! Always easier fixing lighting issues the right way instead of bodging together a temporary fix. Any way to harness that headlight or upgrade the ground so it won't corrode (and offer better performance)?
 

JHZR2

Staff member
Thread starter
Joined
Dec 14, 2002
Messages
47,052
Location
New Jersey
Originally Posted By: sciphi
Good work! Always easier fixing lighting issues the right way instead of bodging together a temporary fix. Any way to harness that headlight or upgrade the ground so it won't corrode (and offer better performance)?
I was thinking about that... The conductors inside the light are really small... But the issue is that there is a set of conductors to the headlight assembly, then a harness end, then the other harness end runs the really small conductors inside the light to the bulbs. So the big question is the gauge of the conductors from the load center to the harness on the outside of the light. The runs inside are small enough that any voltage drop would be tiny, and upgrading would be impractical. But the other runs could be in the cards... If there was some value to it. Thing is, knock on wood, they havent corroded, this was INSIDE! The lights on this car are absolutely awesome, and Ive been pleased with them since day 1, FWIW... though the lenses are yellowing a bit... I suspect the best performance would be had by removing the yellowing haze...
 

JHZR2

Staff member
Thread starter
Joined
Dec 14, 2002
Messages
47,052
Location
New Jersey
So... Any thoughts how hot the backside of the bulb gets? Obviously the bulb itself is extremely hot, but I ha to wonder if I made a mistake with selecting epoxy only good to 180F. I suspect the other plastics have higher melting points; hopefully I'm not going to be redoing this job after my next road trip.
 
Joined
May 30, 2010
Messages
14,037
Location
North Carolina
I wonder if you could make a small heat shield from aluminum. A ring with a cutout for the sockets. Maybe a slight bit of silicone behind the shield to prevent heat transfer to the epoxy?
 
Last edited:
Top