Headlights

Both headlights on my 2002 Nissan Sentra are not working. If it was one I would obviously just got a new headlight, but the fact that neither are working makes me think it is some type of electrical problem. Oddly, when I put the brights on, they work ok.

Everything else in the car is fine.

Any suggestions?

 

You'd be surprised, Brian. You could have been driving for quite a while with only one light and never noticed it, then when the other went, boom...blackness. The bulbs may have been in the car together since new, so if one reached the end of its life, the other was lonely and went after it...lol, j/k.

Seriously, try putting in one bulb. If you have low beam, then go ahead a replace the other, prob be fine for 5 more years.

You can try clicking your dimmer (flash to pass), I think on most cars, both filiments come on together when you do that, but you may not be able to see it if both low's are out.

Don't look for complex problems, until you eliminate the simple ones.

 

I'd try the bulbs first - I've had both fail in the same day.

 

I will give it a try. One thing I don't understand--I was always under the impression that the high beams were just the regular headlights bulbs, only brighter. But since the high beams work but the regular headlights do not, that would suggest otherwise. Is there a totally separate bulb for the high beams?

 

Its a different filament inside the same bulb, just like a 3-way lamp in your house. Low= filament A, High= filament B.

Thats why theres normally 3 wires connected to the bulb.


PS DO NOT touch the glass of the bulbs with your bare hands. The oil on your skin will create hot spots on the glass and cause early failure!

 

Ok, forgive me if I'm being dense, but in that case the bulb is likely fine, right? If it works when I switch to high beam but not when it is on low beam, then changing the bulb won't solve the problem. Sorry if I'm missing something here...

 

No brian, the bulb may not be fine. Have you never had a 3 way bulb in your house, that would work on one setting, but not the others?

Just think of it as 2 single bulbs, inside the same glass tube. They share the glass, but inside, there are 2 wires that will glow for High OR Low, but not both at the same time.

Its not like the old days, when you had 4 headlights, 2 on each side, 1 Hi and 1 Low. Now they basically put both bulbs in 1 little package, but they're still basically 2 seperate bulbs.

 

I replaced both bulbs and still the same problem. Lights work fine on high beam, not at all otherwise. Any ideas? Thanks.

 

You would normally have two circuits (one for the high beam and one for the low beam) one common relay or fuse for both circuits. The two circuits are controlled by the light switch which feeds the two position hi/lo switch.

Some vehicles have two fuses/relays one for high beam and one for low beam. Check your fuse box for a possible blown fuse = low beams. If you have just the one fuse/relay for both hi/lo, the problem is likely in the dimmer switch on the column.

Information concerning your fuses and circuit protection should be in your owners manual or in the cover of your fuse panel.

Hope this helps,

Bob

 

This morning, when I turn the lights on to high beam, the high beam indicator on the console does not come on (but the headlights do). Odd. So I'm guessing this would further support the idea of a blown fuse?