Topic

Good morning everyone, 

So, apologies if this is a repost, I suspect so, but I need some help with my dipped Beam headlights and I have a night time drive ahead tomorrow (hopefully).
So, randomly they both just won't turn on anymore. I turn the lever (?) to position two and rear lights turn on but not front. Fog lights, main beam and park or side lights still work fine. As it's both I suspect it's not the bulbs although I will test that later today. I read somewhere it could be the fuse, but if I'm correct don't both left and right have individual fuses? 

I'm really hoping this is a simple fix.. knowing these cars that is a lot to hope for.

Edit: Silly me, it's a 2002 MGTF 

Yes each headlamp has a separate fused supply.
Its possible the switch itself has become faulty. Its unlikely to be anything else as the main beams work.
I suppose it is possible for both dipped elements to have failed. Have you checked the bulbs?
Also check the electrical plugs on the bulbs, they can deteriorate.

Hi David,

So this got interesting.

I grabbed a multimeter and checked the following:

1) I removed both fuses for left and right, turned the lights on via the steering stalk and checked for voltage where the fuses are usually inserted. One of them, I think RH had a roughly 12V reading, the other one was dead.

2) I put both fuses back in, went under the bonnet to the bulbs, disconnected the wire plug from the bulbs and with the lights switched on, measured the voltage there. Both left and right lights read a 12V measurement. 

​This is odd right? Why would one of the fuse ports be dead but power is going to the light at the front? 

Anyway, I took both bulbs out, and sure enough they were blown and I have an emergency bulb which I plugged in (only one at a time as I only have one spare) and low and behold both lights shine a lovely light. 

So for now, that's great news and I'm about to head off to Halfords to grab a new set.

However, it's strange for the following reasons:
1) why is one of the fuse ports not showing voltage but the light turns on 
2) why did both bulbs blow at the same time given that they were both replaced as a set only 8 months ago. Decent bulbs too, not cheap.

It could of course just be an innocent coincidence - that's certainly how I'll treat this for now, but I think there might be an underlying (small) electrical problem at play.

Either way, new bulbs for now, and I'll wait to see how they get on.

Edit/Update: Bulbs replaced and now working.
 

It isn't uncommon for the first bulb failure to go unnoticed until the second one goes.

The dead supply to one side is interesting. I wonder if there is another supply that's been connected in somewhere to fix that problem, rather than fix the dead supply. 
If you take out the live fuse, does it kill both supplies to the dipped headlamps?

Did you examine the bulb connectors for overheating? The standard connectors are bad for coming loose and creating an arcing situation that could blow the bulbs...

Further to David's comment regarding the connections to the dipped headlights failing, I had that particular problem with my 2004 TF.  I replaced the H7 connectors and local wiring using some that I bought on ebay.   Pictures, including the repair, are here.