Low Beams Not Working

[JoshGC]

My low beams are not working but high beams are. After a bit of research I have checked the fuses in the IPDM E/R (great box that one, thanks Nissan) but they seem ok. I also disconnected the negative on the battery and put back on but that didn't fix it. Beeping sound is heard when I turn on the headlight with the door open so the switch is presumably working.

I have not replaced the bulbs yet as I thought it would be unusual for them to both go at once. Plus the high beams are working which means the bulbs are ok, right? Any suggestions would be appreciated.

(2006 D40)

 

[Kingy89]

Sounds like you have an electrical fualt. wiring issue. blown wire or somehting funny lke that

 

[Old.Tony]

High beam filament and low beam filaments only share the earth, if the low beam wire isn't getting power then low beam won't work.

There is a relay for low beam in the IPDM/ER box (as well as the two fuses). It should be next to the high beam relay.

 

[JoshGC]

Thanks for your replies. So I bought a circuit tester to see whether there was electricity going to the bulb, took out the bulb to check and sure enough... blown bulb. Both of them. I should have checked this first but I had thought it was such a low chance that both would go at once that I had skipped this obvious step. So I have learnt that there are two different elements in the bulb, one can blow allowing the other to still work. Cheers.

 

[Old.Tony]

I would have picked the relay because 1) what the hell are the chances of blowing both lows at the same time and 2) the relay controls both lights, but each light is fused individually.

The next thing to wonder is why both low beams let go at the same time. Although the chance is that both globes came to the end of their useful life at the same moment, it's more likely that something occurred to cause it - could have been a significant jolt?

It makes me wonder what sort of momentary voltages sneak past the regulator when using a high-current load, for example a compressor, or a bank of driving lights, or a 1200W sound system cranked just as 'Black Betty' starts.

 

[JoshGC]

Considering I had changed one of the bulbs only a couple of months ago makes the chances of their useful life syncing next to impossible. Something must have gotten past the regulator. Everything is stock standard though so I don't have anything that would change the current. Although......... speed bumps! I was driving into Dan Murphys last night via a number of speed bumps (real ones, no shortcuts), lights didn't work when I drove back out. I didn't think that I had gone over them unusually quick but the bulbs may not have liked the jolts? Surely they are built to withstand harder bumps than that. Oh well, will just have to satisfy my thirst slower next time.

 

[Aussie Frontier]

I have had decent quality globes last only a few weeks .You never know how they were treated before you bought them. If the stock boy used the box for soccer practice the lights are weakened.
Sometimes its a case of sh1t happens