Main beams not working while other lights do

Technical Area Electrics & ICE
1
  1. My model of MX-5 is: NC 2005
  2. I’m based near: Scotland
  3. I’m looking for technical help or recommendations on:

Hello folks. So, disappointingly last night when I went to drive my car home at night both the main beam headlights would not come on. This was a real pain as I had an hour’s drive to get home.

I don’t drive the car much at night, so I could only say with absolute confidence that they were working in march at the MOT.

Anyway, the thing is that the high beams, fogs and side lights are all still working (making for a fun journey juggling the three), so after checking the fuses which are fine, I think that also rules out the relay, is that correct?

Of course it could be the bulbs, but both being out seems unlikely in my experience.

What does that leave? The switch perhaps?

2

I’d check the bulbs before doing anything else.

2 Likes
3

I had a guy work for me and when a mondeo came in with no headlights working he immediately wanted to use a scanner to diagnose :see_no_evil:

I insisted he checked bulbs first…….
Guess who was right!!

Needless to say he doesn’t work here now.

Youth of today……… I’ve forgotten more than they will ever know

4

Yes, it could be the bulbs, both of them in the last few months I suppose. It’s possible.

Not that easy to get to, mind.

5

Definitely check the bulbs. My son had both fail at the same time a few months ago (like yours, they failed when they were ‘off’ or being switched) and both dipped beams had failed.

It’s not uncommon, so I’d suggest a single cause rather than a coincidence. Some sort of surge or spike for example. I’m not suggesting looking for it, but I’d bet on the bulbs.

6

If not the bulbs, check the wire to the adapter that attaches to the bulb.