Long time lurker, this problem finally gave me incentive to register and post.

I have a 2007 G35 sedan with 60k miles. Recently had to replace the battery secondary to it failing after the car sitting for a while before coming back from a trip. Ever since then my headlights haven't worked, high, or low. The turn signals, fogs, and park lights all work. Checked all the fuses in both battery area fuse boxes and next to the driver kick panel. The switch works (the little blue headlight symbol comes on when I flash the high beams), and I can hear a relay switch on when I hit the high beam switch, but no head lights.

Anything else to check before I pull the headlights? I can't see how it would be a bulb if both sides went out at the same time. This is driving me crazy!

Thanks in advance for everyone's help.

 

it could be the bulbs, iv had both my bulbs go out a few times on my previous cars and is a bit weird but not impossible or anything like that... imo since uv checked everything else and you can hear the relay then it is the bulbs or the ballast which is much less likely to go out at once.

First just loosen the ballast from the back of the bulbs, remove the bulbs and re-seat everything(how to in DIY section if needed) to see if something might have been knocked loose, then check all the wiring for the lights.

Checking/replacing the bulbs is very easy through the wheel liner as can be seen in the DIY section here, try borrowing a d2s bulb from someone you know since these bulbs are quite common now on newer cars, else you can buy a set of 2 for ~$20 from ebay to check and they work great, iv had them for over 4 years without issues. If its not the bulbs, relays, fuses then it might just be the ballasts

 

Perhaps the fuse went out while switching batteries?

 

^ he said he already checked all the fuses and relay in both compartments...

 

Ok got the bulbs and switched one side out. Still no lights. Anything else to check?

 

^ got ur pm, well if u are 100% certain that the fuses are fine and changing bulbs correctly does not cure the issue (making sure the ballast connects correctly with the bulbs and that the butterfly clip holds the bulb fine) ... then there is only one other possible issue that i can think of: ballast and/or bulb igniter(aka hid control module little black/grey box with solver connector that connects to the bulb). These can be bought used off of ebay or marketplace on these forums but are not that cheap (maybe between ~$50-80each)

Again i cant tell you for sure over the net what the issue is and am not telling u 100% that this will cure the problem but this is the only possible issue left IMO if all fuses/relays/bulbs/connections are fine...

If this does not cure the issue then you can always resell the ballasts/control modules for good price.

let us know what you decide to do and how it works out

 

Given how much does remain working correctly, it seems unlikely, but whenever there is 'logic' involved in a circuit, it has to be a suspect when weird symptoms like this occur; especially after a power related event. In this case, I am referring to the BCM (body control module) and the IPDL (I forgot what it stand for, but it powers the relays). The BCM is the 'brain' here and can be talked to with diagnostic equipment (usually dealer). If I were you, I'd download a copy of the Factory Service Manual for free for Infinitihelp.com (you have to register first, also free) and read up on the headlight circuit and function. I can't say for sure, but it's also possible for the headlights to be tied into the security system too I guess.

 

Update:

Ran the "auto active test" which tests the IPDM. Everything worked except for both headlights. This definitively rules out the combination switch or BCM. The high headlight relay was working fine also.

The only thing it can be at this point is the IPDM, or wiring. After looking at the shop manual there is a separate low headlight relay mentioned as being located in the IPDM...but when I look in the IPDM, I don't see an actual removable relay. Is this relay integral to the IPDM, or am I looking in the wrong place? If this relay were not functional, it could prevent the lights from not turning on.

 

Have you verified that voltage is not present at the headlights when they are switched on?

 

No voltage to the headlights.

From what I can tell, the low headlight relay is integral to the IPDM, but before I spend 200$ on a used one, is the relay actually somewhere else and I'm just missing it? The pre-2006 cars had a separate, physical relay located alongside the fuses in the IPDM. Either Infiniti moved it or integrated it into the ipdm

 

In the 2007 FSM, in the Exterior Lighting (EXL) section, on page EXL-11 where it shows the location of the system components, in table form it subtly states:

IPDM E/R

Controls the integrated relay, and supplies voltage to the load according to the request
from BCM (with CAN communication


Then on page EXL-88, there is a schematic showing the IPDM with the relays clearing included within the "component" box, indicating integral/internal components. You can see the pin numbers and connector numbers there too, so it should be possible to verify whether the voltage ever "leaves" the IPDM or not. This could eliminate the possibility of bad wiring between the IPDM and the headlight.

I have never had issue with, nor had reason to troubleshoot the IPDM circuit, but I have heard others mention problems with them before, even to the extent they thought in was fairly common and widespread among NIssan cars in general. I thought notion that was rather exaggerated, given that the only instance I've observed on this board has been when it was flooded by clogged drainage around the battery compartment, but maybe there's more to after all.

SInce you've verified the voltage isn't reaching the headlights, I suggest reading up on the schematic and verifying the voltage isn't present for the headlights at the connector exiting the IPDM. If it isn't, and you've checked the basic functionality of the BCM, then it seems the IPDM would be looking pretty guilty at that point.

 

Wait Wait Wait . . .I just reread your original post. You said this all began after a battery replacement. The IPDM is in the battery compartment. Have you pulled the battery out and verified the connectors to the IPDM are all properly seated and there is otherwise no physical damage/compromise to the module. My hunch is that, being heavy, awkward, and rather cramped during the battery replacement procedure, something got bumped/banged/bent/crushed etc. Hopefully, it's just a connector re-seat is all. I'm crossing my fingers for you.

 

I just checked all the connectors again. No damage to the IPDM. All connectors were seated. Checked through the headlight hi/lo outputs. When hi is selected, it gets a nice 12v from the IPDM. Nothing on low. If I run a jumper that is connected to 12v to the headlight low output, the headlight turns on.

Looks like it's the IPDM, right? I've checked and eliminated the combination switch, BCM, and any problem with the headlight wiring or lightbulbs.

 

SO is that to say that you have voltage at pins 89 and 90, but not on pins 83 and 84 ?

Have you checked the 15A fuses # 56 and # 57 on the IPDM that are shown in the schematic?

 

Use a voltage meter and check the voltage on the harness see if it reads 12v if it doesn't try to trace the wiring to figure out the problem