Hello everyone,

My headlights turn off when I put them on high-beam. The blue light turns on in the dash but the bulbs turn off. Could this be a fuse issue or something else? And where would these fuses be located? Any help would be appreciated.

 

There's only a single bulb that does both low and high beam so I'm pretty sure there's not a separate fuse. The low and high beam is controlled by the ballast. If they BOTH act this way (left and right), that's odd and not likely to be an issue with the ballasts. Both failed at the same time ? Doubt it....

Looking at the FSM, there's a 'high' and 'low' beam relay. I guess that's as close to a (shared) fuse that you'll get. Check that relay (most likely in the underhood fuse box area). You might see a visual indication that it's failed or pull it out and shake it a bit. If it rattles, that's a likely sign it's failed. Relays are somewhat generic or universal so there may be another relay in this fusebox that's the same specs and if so, you can swap it quickly to test. Even if it's something like, say, a fuel pump relay, you can swap this one temporarily because you don't need to start the car to test the headlights.

 

Yep both turn off. I just bought the car about a month ago, and it already had this issue. So I don't know if it were to be the ballasts, that the ballasts both failed at the same time or if they both developed this issue at separate times.

Will check out the relay first though.

 

The relay for this isn't under the hood from what I saw when checking.

Sorry, it looks like there are fuses for the high beam operation - one for the right (# 55) and one for the left (#54). They are not located in the 2" x 6" box in front of the battery but are in a larger enclosure. The manual refers to "engine room" so I presume that means under the hood.

 

Hi beams have two separate fuses in the IPDM, left side is fuse 54, right side is fuse 55.

Remove and inspect the fuse, if it's good then take a DMM and probe those fuse slots (or the top of the fuse if they have serviceable exposed leads) and have someone cycle the hi beams on/off. If you have switched voltage at the fuse then the IPDM relay probably fried (internal, non-serviceable) or you have broken wires leading to the headlights. Replace the fuses and check for switched voltage at the headlamp harness.

If you do not see voltage present at the fuses then you possibly have a bad BCM.

 

Thank you both! I have been searching for a while now for a diagram or something to find where the IPDM is. All I can find is pictures of the V35 IPDM. I did find one video of a G35 coupe. Is the access to the sedan IPDM the same as shown in this video?

 

Surprised nobody suggested checking the bulbs.

 

I just replaced the bulbs 2 weeks ago. Should've mentioned this before, but I think we talked about this in another thread which might be why @Hall Stevenson and @cleric670@gmail didn't mention that.

 

The field service manual has a simple 'drawing' of the IPDM and that looks exactly like what they show. Some fuses along the outsides and those (2) vertical things in the middle.

Just watched the video and yes, this is where fuses # 54 and 55 are. I looked at mine yesterday and saw this box but it's partially covered by the battery shrouding so I didn't dig into it further.

 

I generally don't believe in coincidences like this where (2) different bulbs will fail at the same time or (2) different fuses fail at the same time. Can it happen ? Sure, it can but I'd look elsewhere first.

 

The bulbs work in low-beam mode. And perhaps the high-beam fuses failed at different times but the previous owner just never checked/changed them. I can't know if they failed at the same time as this is how I got the car. Really hoping its just the fuses.

 

I suspect you'll find both fuses blown and replacing them might be the solution and the end of it. When a fuse blows though, or in this case, (2) blow, you have to ask "why?".

 

Why is easy, OVERCURRENT PROTECTION.

 

Yeah, but what caused it to need to go into "overcurrent protection" mode is my point.

 

I hope so too. The "why" may be because of the numerous modifications. It may not even be the fuses, based on the mods. When buying, I could see the lights were modified a bit, but this is not the sort of stuff you usually check for. Lesson learned. There are LED rings in the housing around the projectors which turn on with the lights. Whats weird is the foglights and the LED rings are always on (when the headlight switch is on), but the main headlight bulbs only turn on when the foglight switch is turned on. Could it be that the headlight signal is being sent to the fog lights and LED rings, and the fog light signal is being sent to the headlights? One indication of this could be if normal foglights turn off on high-beam. So much complications.

Still haven't checked the fuses because I couldn't get the clips out. Will buy clip removal pliers tomorrow.