Very weird issue going on with the main headlamps. The other night I turned them on and nothing. So I turned the switch back to off and then went to fog lights. They work....I then switched to headlamp mode again and now only the left one came on (drivers side - american car). I get out of my car and see the right side one is off so I just barely tapped on the lamp itself with my finger and it comes on!!!! Both lights working again. Drove all night...went out to where I turned the car off again...came back out and the headlamps fired right up as they should.

So, tonight I decide to just test them in my garage again. So without the key I tuned the switch to fog lights and they came on but when I switched to headlamps nothing came on again. I am wondering also if main headlamps will not come on unless you have the key in the ignition or the car running? I never thought about that. Anyhow...I go get my key and start the car. I turn on the headlamps again and this time it is the reverse. The left lamp is out but the right one (passenger) is working!!!! What the heck? So I did the same trick again and just tapped with my finger on the front of the headlamp glass and the light comes on.

Ok...I am going to assume something is loose in the wiring somewhere. Pretty sure the switch is not bad since all the fog lights function as normal and the high beams work.

So maybe someone here can give me a starting point and also tell me if headlamps come on when the car is off or is that a feature to not drain the battery? I know the lights are not burned out and everything works (when it wants) so what are the first things I should check and maybe it happening to BOTH front lamps at different times might provide a clue?

Thanks you for your time

peace out,
daddylogan

 

Logan, do you have HID bulbs or standard halogen bulbs? I am betting that you have standard halogens. If so, odds are, your problem is the connector on the back of the bulb. This is known to get flaky and cause random issues. I would start there.

 

Standard bulbs Thermo...nothing has ever been altered or changed. So, how do I get to the connectors on the back of the bulb and how do they get flaky? LOL - If my understanding of this is correct they are clip on connections which seem nearly impossible to come loose and I certainly hope I don't have to remove the bumper.

The just being able to barely tap them and they fire up is so weird and what are the odds that both connections go flaky at the same time? Or would it only take one to go weird to mess up the whole circuit?

Did a ton of research last night and found one place where a person said it more then likely is the switch itself (which is easy to replace) but still, the tapping on the bulb and having it come on might shoot that theory down. I guess bottom line is all the lights work, just the main headlights work when they want.

So...what procedure should I approach today Mr. Thermo? Where should I go jiggling things? LOL

Thanks as always...been a while since I have been here and nice to still see you active!

peace out,
Logan

 

Logan, what happens is if you look on the back of the bulb, there is a single post that sticks out of it. The connector that goes on this is not really rated for the heat that the bulb emits. So, the wiring starts to get burnt and the connector will start turning all sorts of colors. This is oxidation on he connector. This oxidation is a high resistance, which only makes the connector run that much hotter. By tapping on the headlamp, you are shaking the headlight bulb and then this connector which can sometimes make it move just enough that it will make better connection and light up.

As for accessing it, yes, you have to remove the bumper cover. You can try reaching around on the back, but remember that the internals of the headlights can become brittle, especiaily under the high heat of the bulbs. So, it is best to pull the bumper cover off and then pull the headlight assembly so you have room to work. Once you get access to the headlight assembly, you will want to replace that wire that runs to the center post on your headlight bulb. This would probably be a good time to look at the pins in the connector to, just in case that the problem resides there. You see pins that are not silver in color, that is a high resistance connection. A gentle scraping with a knife or scribe to get it back to silver in color will be what you want to do.

If you want to prove this, I would say to find a time when your headlight bulb is not lighting up, pop the hood/bonnet, gently remove the cover off of the back of the headlight, then reach in and gently touch that center connector. I bet as soon as you touch it, the bulb is going to light up.