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Headlight wiring problems

brh76's Avatar
CF Beginner

Join Date: Sep 2011
Posts: 1
Parry Sound, ON

September 12th, 2011, 1:12 PM   #1  
Headlight wiring problems

I have a 2007 Uplander and I am having a problem with the driver's side headlight. The wiring harness is shorting and melting the connector right at the bulb. When i first saw the bulb out I bought a new bulb then when I went to replace it I saw the connector all melted. I ordered a new wiring harness from GM and installed the new wiring with the new bulb and after 3 months the same thing happened again. This time the connector was melted much worse and the bulbs was also showing quite a bit of heat damage and warping around the connector. Fuse is not tripping even though there is an obvious short. The connection between the bulb and the harness is just heating up to the point the plastic connector is quite distorted and the metal contacts are heat damaged and warped to the point they don't make contact. It is happening on the live wire and not the ground wire.

Has anyone else had this problem or have any suggestions? Local GM dealer said that short of replacing the main harness and relay, they had no suggestions because it took three months to short out so it would be very difficult to trouble shoot. They said they had never heard of that problem before.

fscoles's Avatar
CF Junior Member

Join Date: Mar 2009
Posts: 34

September 15th, 2011, 12:48 PM   #2  
I think your '07 Uplander headlamp circuit, harness and plugs are the same as on our '08 model. I don't know the answer to your car's problem, but I have a list of things you can easily check for the possible problem(s). I assume you know how to easily remove the headlamp housings to get at the lamps and the parking lamps. First, and most important, the stock headlamps must be the H11 regular (OEM style) 55W lamps....each of your four lamps (L&R Bright, and L&R Dims) should be stamped 12V/55W on the plastic base on each lamp....many of the aftermarket H11 lamps are stamped higher than 55W, like 100W...those lamps run alot hotter and may (or may not...depending) burn out the sockets and harness as you've described. Honestly, if anyone needs a brighter lamp than the OEM H11, then they're either driving too fast or need to see an eye surgeon & turn back their Driver's License to DMV. Many Ebay & other vendors say you can use higher wattage headlamps...but it's not wise. Second, if you drive along an ocean or in winter salt country where corrosive salt air corrodes the socket contacts, then take them all apart and clean them out by spraying them with contact cleaner spray & then dab in some electrical or white lithium grease into them and reassemble....the grease helps keep corrosive salts out. Third, most GM vehicles do not have a fuse on the headlamp ckt....there's a large mechanical Circuit Breaker located inside your engine compartment's fuse box....if that CB is weak or corroded (a common occurrence) then it will not trip out even if you've dead shorted the circuit, which will either burn out the sockets or burn up your car.....replace that circuit breaker as it costs little...your owner's manual has a diagram listing which breaker it is. It is a CB and not a fuse, because of driving safety....a good spring-activated CB will retrip itself after an overcurrent episode....a blown fuse doesn't fix itself. There's also a few more CB's in that same box....like for the wiper motors and sliding doors...if one CB's bad, then replace all of them. Spring activated CB's get weaker with each activation....so if it has tripped out more than a few times....then it needs replaced. The headlamp relays are also plug-in's which cost very little from your local parts store; you may also want to replace them, as they can also give out over time, especially on the high-amps headlamp circuit.Tired or corroded headlamp CB's can burn up your car. You can also splice in replacement lamp sockets to the harness wires if the old ones cannot be made like brand new....do not use solder, instead use automotive crimpable splice connectors. If a lamp's harness socket has been overheated in the past, it must be replaced with a new socket because the heat usually permanently removes the spring tension from the metal contacts. It doesn't require a Chevy dealer to do any of this type work. You can be sure that when any electrical connector gets too hot to touch, then that connector isn't making good contact....in effect, it's acting as a heating element, not an electrical connection; also, if that bad connection gets wet (road salt, for example) then it will also act as a Rectifier...not good.

It's now several days after I had posted above...after looking at our '08 Uplander Owner's Manual and looking inside the fuse boxes I see its headlamps are supplied from four fuses, a fuse for each of the four headlamps....I apologize for the wrong advice. Some older Ford and Chrysler cars and minivans we've owned in the past did have headlamp circuit breakers that would reset on their own. Fuses are fine and safe, but you have to replace them if they blow. Headlamp connectors/plugs have spring tension in their contactors, which is essential to keep it from coming off and to insure good electrical contact, so it should get replaced if it got too hot and lost its spring tension/temper. When replacing an automotive fuse, it's a good idea IMO to use only a known-good domestic brand (like Bussman or Littelfuse) because there are reports that some of the "economy" fuse assortments don't blow when they should which can be dangerous.

Last edited by fscoles; September 19th, 2011 at 11:49 AM. Reason: Uplander headlamps have fuses, not Circuit Breakers
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