Headlight continues blowing out, 2006 Nissan Xterra

Hey folks,

My brother-in-laws Xterra has started blowing the passenger headlight out repeatedly. We have two issues and I need to read the codes for it, but it's started cutting out while driving and hard starting as well.

The headlights issue is odd, they changed the bulb - tested fine and then the next morning was blown. The bulb was disfigured and had a balloon out the side. They changed it again, and then 3-4 or drives and it was blown again.

The driving issue, one time it died while he was driving and then restarted immediately - he was going 65 and he didn't need to turn the key. It's been hard starting since then. And has had a few new more instances of it doing that while driving.

I'll get more info ASAP, I need to get a multi meter on the light and try to pull some codes. I'd love some thoughts, they're short on money and time so I'm trying to get this fixed as soon as I can.

Thanks guys!

Maybe a grounding issue?

Any possibility of water in the affected headlight? I've had that problem before, drilling drain holes in the headlight housing was a temporary fix that has continued to work

accordionfolder said:

Maybe a grounding issue?

I'd start here. 

I say meh on the grounding issue, as that would result in lower voltage to the bulb instead of higher. Dumb question, are these bulbs ordinary/old fashioned filament bulbs, or something that needs some sort of controller module? If it's the latter, I'd start with the module.

Is anything else on the car acting up? If the alternator voltage regulator went wonky, it could be feeding higher than normal voltage to everything, hence the question about how the car is acting overall.

I too was going to say voltage regulation.  On these, is the voltage regulator in the alternator or is the regulator a separate unit?  

Some googling says that the voltage Regulator (VR) is internal to the alternator.  In that case, get a volt meter ($7.99 Harbor freight) and with the car running, like shown in this picture, the voltage should be more than 12v and less than 15v.  Like the pictures which shows 12.28 volts.  If its reading something 15 or more, the VR is not regulating correctly.  

Another visual symptom of to much VR could also be a swollen car's battery.  Its the swollen headlamp bulb that made me think too many volts.   

Would be really curious what voltage at the battery is with car off, car idling, and car at 3000 RPM.  I'm wondering if the alternator is charging this thing way over spec, like 15V or higher, and the battery is getting cooked (hard starting) and the ECU and such is Not Happy (runs like butt) and the bulb is catching the worst of this situation.

It's overcharging, the voltage regulator is in the alternator in the Xterra, so replace it. 

I'm seeing 13.9v at idle and rev'ing it to 3k I'm only seeing 14.2. it's a cold night and it hasn't been run in a while, should I drive it and then test again? I'm getting no stumbling, etc on the 15 minute drive home.

Had to prop it up so I could rev it (DBW), haha - that says 14.19

I can't feel any bulging in the battery, for whatever that's worth as well. It's cold so I'll get back to testing tomorrow morning. I'd really like this to be the alternator, that'd be straight forward!

I had the same problem on a different car. It ended up being the ground wire to that light. That's the reason why I said look at that. 

If it was the voltage regulator, other light bulbs would fail, not just that one over and over. 

In reply to Slippery :

I'll try and check in the morning, I'll have to find where all the grounds live!

In reply to accordionfolder :

It was the ground wire to that bulb. It was corroded and not easy to see. I would try and double it up with a new ground to test. 

In reply to accordionfolder :

Check captainawesome's Audi thread, that's the problem I was having:

https://grassrootsmotorsports.com/forum/build-projects-and-project-cars/2011-audi-a3-tdi-hatch-bargain-or-dumpster-fire/272082/page3/

Okay, at 14.19v it's not the VR.  Good.  

Wiring:  Rock Auto show listing and part numbers of inexpensive replacement headlamp sockets.  

Some they show have bare end wires:  

Others are more of a connector-to-connector type:  

Weird. 

It still seems a stretch that an intermittent connection is causing current reductions that pop the bulb. Questions to the OP:

While the bulb is working, is it brighter, dimmer, or the same brightness compared to the opposite side?

Does its brightness vary when the engine is rev'd, differently from the opposite side?

Where did these bulbs come from that keep popping?

Is the opposite bulb still OEM original?

I once bought replacement headlight bulbs and both burned out in a few months - they were crap. Went back to OEM and they never failed again.

Are they touching the bare bulb with their fingers?  I did that and had bulbs pop almost immediately.