2010 TD4e HSE ... yesterday was the first cold day I've experienced since ownership last October. Started her up in the evening ... 2C showing on the external temp readout. Drove a few yards & noticed the weirdest light pattern from the headlights! Seemed dimmer than usual and projecting a trelliswork pattern! i.e. diamond shaped latticework (as in playing cards diamond shape) ... the sort of trellis you used to be able to buy in lengths and it could be sqeezed together & made higher or opened up longer and shallower.

Well ... this effect disappeared after a few minutes & the headlights (dipped) had returned to full strength. & this is after returning from fairly long run the same afternoon.

Has me wondering about the battery/charging system effectiveness and whether there's a link?. Always thought the starter motor rotation speed was a little slow compared to all other cars I've owned/driven. Spent a few days at Center Parc, Longleat this week, drove up Monday daytime via Taunton ... gentle drive, c 70 miles or thereabouts. returning yesterday, went back to the car in the morning (not particularly cold, 5C I recall) and the starter motor turned over much more slowly than usual slowly tho she fired up in a couple of seconds or so. Now that should not happen after just 4-5 days standing with a fairly new vehicle only 21 mths old (& especially the beefed up e version). Thought also I'd come across earlier posts about poor battery grounding, but cannot recall if that also applies to more recent production?

Anyone else come across this strange dipped headlight effect?

Mine do that if I use the washers with the lights on, the water running down the lamp cover produces weird patterns, the water may freeze if cold enough.

I think the grounding "problem" can be associated with all models and years.

Without a 'good' ground the car just won't work well. 2002 Honda VFR800
2002 Toyota Celica 140 Silver (mid life crisis - again!)
2007 FL2 GS Manual Army Reconnaissance Green + freel2.com sticker
2004 Toyota Celica 140 Black - Gone
2000 Toyota Celica 140 Silver - Gone
1998 Toyota Celica ST Pearl Green - Gone
1996 Nissan Primera 1.6 - Gone
1994 Rover Montego 1.6 Auto - Gone

taztastic wrote:

Mine do that if I use the washers with the lights on, the water running down the lamp cover produces weird patterns, the water may freeze if cold enough.

Hmmm?
Condensation?
Frost?

I was going to say that taztastic. Definitely does it when I use washers. Perhaps melting ice or condensation is the answer then. LL.B (Hons) - University of Derby
LOT (Lord of Time) - University of Gallifrey

Sorry, but neither ice or condensation ... I was so amazed I got out & looked!

Mushrooms....as in magic ones

A bad earth could certainly cause a dimming, the lattice effect is weird though, it really is only explained by something in the beam, try the headlight washers and you will see what I mean.
Be interesting when you find what is the cause.

Probably due to vibration caused by the DMF about to fall apart