Headlight plug melting

thawaxshop

Original poster
Member
Dec 2, 2012
14
First off yes i have searched and all i found (http://gmtnation.com/f23/headlight-plug-burnt-out-again-1730/)

I have an 02 Trailblazer. When i bought the truck someone had those cheap "blue" high watt headlights in (this was 3 years ago) after a few months they blew. I bought regular one to replace and noticed the whole socket had melted, so i went out and bought replacements wired them in and went about my way. A few months later lights go out again (wtf) take them out and i see that these new ones have also melted..... So i go to my local auto parts store and got big ol' beefy 12ga monster harnesses and wire them in. In a few months guess what? You guessed it the heavy duty ones melt. So at this point im guessing the headlight inside is fubar'd so i order new (Aftermarket non fancy basic OEM style housings) and plug and play few months later melted again..... So i went out and bought an HID kit and want to wire this in but FIRST i need to figure this all out. mind you no fuse blows so IDK wht the deal would be. What i was thinking was i can run a new harness to the bulbs (from the fuseblock and coming off the correct fuse for the lights) and that may fix this finally. Now is there anything in there thats special? Or can i just run new wires from the fuses to new sockets (which ill be putting into a ballast) and ground it to the battery? Or do the grounds also have to be in a specific place?
 

gmcman

Member
Dec 12, 2011
4,656
What exactly is melting, the plastic connector on the factory wiring or the plastic body of the headlamp?

Something tells me the connections are dirty and causing excessive resistance, only a hunch.
 

MAY03LT

Member
Nov 18, 2011
3,420
Delmarva
thawaxshop said:
So i went out and bought an HID kit and want to wire this in but FIRST i need to figure this all out. mind you no fuse blows so IDK wht the deal would be. What i was thinking was i can run a new harness to the bulbs (from the fuseblock and coming off the correct fuse for the lights) and that may fix this finally. Now is there anything in there thats special? Or can i just run new wires from the fuses to new sockets (which ill be putting into a ballast) and ground it to the battery? Or do the grounds also have to be in a specific place?

I asked the guy in that thread if he used the harness but he never replied. I assume that he didn't. Best thing to do is get a relay harness for the HIDs and a new connector for the drivers low beam bulb. With the relay harness, the connector for the drivers low beam will be used to turn on the relay (minimal amperage) instead of a 35w ballast and won't be at risk of melting again. If the wiring inside the light is too messed up to repair, you can get the low beam B+ and ground right at the headlights big 4 pin connector and use that to turn on the relay.

I don't know if you've read up on getting HIDs working correctly, but since it sounds like you want to get this thing right, I'll post this anyway. Asides from the relay harness, the DRL signal has to be turned off or modified. There are a lot of different ways to do this, many are posted in the article (or article submission) section.
 

jrSS

Member
Dec 4, 2011
3,950
Cuz the week ass stock wiring aren't made for hid bulbs. You need a relay harness so that shit doesn't melt.
 

NinjuhhNutz

Member
Oct 15, 2012
720
You were using oem lights and halogen bulbs, and the harness kept melting? I'm glad you didn't PnP the hid's without a relay harness, then. :no:
If it were an issue in the wiring before the actual 4-pin connector and harness, I would think it would have blown a fuse? And if it were the connector/harness, then the issue would have been solved by replacing it, as would changing the light (housings) themselves.
I'm curious to see what fixes this one...
 

MAY03LT

Member
Nov 18, 2011
3,420
Delmarva
NinjuhhNutz said:
If it were an issue in the wiring before the actual 4-pin connector and harness, I would think it would have blown a fuse? And if it were the connector/harness, then the issue would have been solved by replacing it, as would changing the light (housings) themselves.
I'm curious to see what fixes this one...

There was also a time or two where folks went as far as bypassing the dinky wires in the headlight altogether, so beefier wiring went direct from the 4 pin wires to their fancy hi temp connectors and still cooked them (they were plain jane halogens).

I read a thread a while back where a few great minds went in depth about the PWM signal. I don't remember the exact details since they were talking about stuff like electrons and transistors and dilithium crystals, but I got the gist of it and it led me to believe that it is the root cause. I've had a few of these here that were repeat offenders and so far so good with long term fixes, including 2 that kept drl/perimeter, just by removing/modding the PWM signal.
 

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