# HID car light doesn't light up



## monkeyboy (Mar 25, 2006)

I'm having a problem with one of the HID lights on my car. It fails to light up about one in five times. I just switch it off and on again and its OK. Any ideas as to what might be causing this?
Could it just be a bad contact?
Could there be moisture in the system?
Do i need to change the bulb, ballast or both?

Any help would be appreciated.


----------



## Changchung (Mar 25, 2006)

Hi, try unplug and plug again all the connectors, them used normal, if the failed continue twist the ballast and check again, for me is a bad contact...


----------



## monkeyboy (Mar 25, 2006)

thanks I'll try that.:candle: 

Is there any chance of electric shock if I don't actually switch the light on?

any large capacitors that remain charged after the light is switched off or anything?


----------



## Changchung (Mar 25, 2006)

Just for case use some gloves, although I do not believe that it keeps load... Anyway, with the swith off is no current or volt in the balllast...


----------



## monkeyboy (Mar 25, 2006)

I want to make make sure before trying anything.
I'd imagine that 25000V would jump straight through a pair of rubber gloves 

much like being zapped by a stun gun.


----------



## cmacclel (Mar 25, 2006)

You have nothing to worry about. What does the light do when it won't turn on??? Does it flicker first?


Mac


----------



## monkeyboy (Mar 25, 2006)

Its hard to say when I'm inside the car. I think it does flicker first.

If it flickers, does it mean its the bulb that needs to be replaced?

If it doesn't, is it the ballast?


----------



## Daniel Ramsey (Mar 30, 2006)

I have found that the general culprit of the HID lamp not igniting is insufficient voltage, other than the possibility your stock wiring may not be heavy enough a scenario that I do know of is if your vehicle has Daytime Running lamps or the Auto On feature the headlights are on while you start the car and the draw of the starter reduces the voltage enough that the igniter phase fails to get enough high voltage to strike the arc.

Solutions?

First check all your connections, check battery connections, its voltage state and the starter draw, the starter if new should not be a concern but if your vehicle requires a lot of cranking then you should look into why.

Solutions?

In the case of my personal vehicle a 2002 Silverado 3500 with a 496CID (8.1L) with a dry cell battery my HID lamps may not start if its dark enough to make my AUTO light system go on, while I"m starting the truck the low beams (the HID lamps) are on at the same time, what I do then whenever I turn off the truck is to preset my high beams on instead, then after I start the truck flip the beams to low. This gives the HID ballasts sufficient voltage to ignite.

My other vehicle has an identical 4 headlight system and HID lamps but never has a problem, but it has a much smaller engine that doesn't draw so much amperage off the battery.
I could come up with a regulated power converter or disable the auto on feature but I just make sure the HID does not go on when I'm starting the motor.

If none of this applies in your case it may be neccessary to run some heavier wire and use relays to the ballast, even though most HID are a 35 watt lamp during the igniting sequence you have a heavy draw to create the higher voltage,I suggest 12 gauge from battery split to two relays, having a 25 or 30 amp circuit breaker is a wise choice on that section, 14 gauge from the relay to each ballast, 15 amp fuse for each ballast/ lamp relay. Each ballast has its own relay in other words. Most cars use a 16 gauge wire to each headlight also the return ground wire of which would need to be at the very minimum a 16 ga though I prefer 14 ga to a good ground back to the battery or body ground. The body ground must be good to the battery, many vehicles have poor grounds and if you have a lot of other stuff like power heating, seats, radio/amps then you should investigate the ground wires.

On another Silverad but with the Duramax diesel I installed HID kits, same problem of the lamps not igniting so I told the owner to always turn on the high beams when shutting off the engine, the headlights automatically shut off on the Silverados with the Auto On features.

To get geeky I could have an optical sensor at each headlight or coupled to a piece of fiber optic so that if the photo cell does not get light it automatically restarts the lamp not working, simple really.

Hope all this works.


----------



## Daniel Ramsey (Mar 30, 2006)

While I was making my breakfast I just realized that some vehicles do not have seperate lamps for the Daytime Running Lights but instead with a photocell in bright sunlight turn off the low beams and instead light up the high beams on reduced voltage, my wifes Pontiac Aztek is set up like that, her low beams are HID but like all my HID installations to date I suggest having Silvania Silverstars on the high beam so the driver has "instant" light available instead of waiting for a cold ballast/lamp to heat up.
Even a 50% voltage reduction on the high beam circuit of the DRL will still turn on the relay if your vehicle has the HID setup for high beams, however during daytime driving these lights will be too bright to use and aimed directly at oncoming traffic and technically illegal and unsafe. If that was your setup I reccommend disabling the DLR or reroute that function to some seperate LED fog lights, I say LED because I have the Deno 3 lamps and they will not burnout like a regular lamp, just keep in mind the DLR on some vehicles in sunlight conditions may be reduced voltage so it will not work with 12v led lamps or HID ballasts. Daytime Running Lights is a good idea but too often I see them burntout because they use the high side of a 3157 or the 3156 which is not meant to run all the time, they also burn up the sockets. Replace with a latest generation LED lamp that will allow full time use of the bright side of the lamp or replace socket to use just the low side, I've had cheap LED 3157s burnout because they were running all the time like the brake light was on and they were overdriven big time. Using some 3watt Luxeon stars are an excellant idea for DRL uses, I like my blue ones, even made some green, that really gets peoples attention.

Eventually the auto makers will get their act together and have all this ready for us but for people like me who tinker to upgrade often we need to work around whats supposedly safer technology and make it better higher performance quality.


----------

