Head (and tail) light problem. Lights come on with ignition key - switch has no effect.

Aug 1, 2020
2
0
2011 altea 1.6tdi eco with 90k.
Generally been a good car for past 6 years. Only previous problem was EGR valve failure which was expensive, just before diesel gate. At least diesel gate explained why I got nowhere near the claimed mpg (my previous car, clio dci exceeded combined mpg rating, even after 115k!)

Just had 2 problems, believed to be unrelated.
Firstly, I noticed the other day that the dipped headlights and side lights seem to be permanently on when driving. They come on when the ignition is turned on. Fortunately they go off when ignition is turned off so they don't flatten the battery. I don't have Xenons, so no daylight running mode (and tail lights shouldn't active in Daylight mode). Not critical but worried it might be forewarning of a more serious problem? Has anyone else experienced this?

Second problem was that a day or so later, the clutch pedal went to the floor and didn't disengage drive. Car effectively immobile - fortunately at home. I topped up the fluid with new DOT4 and pumped the pedal by hand, but could hear a hissing noise and pedal never regained usual feel, and fluid leaked onto the ground near the master cylinder. I found a local mobile mechanic who suspected a leak in or around the master cylinder. He was able to source a replacement and fit it within 24 hours, and I thought £250 was reasonable. Great service. However, I'm not impressed with VAG build quality.

Now back to the lights on problem. I've since had an occasional bulb failure warning message, but warning doesn't stay. As all lights work, it sounds more like a wiring or relay issue. Is there a lights relay as I can't find any info on one? Other options could be the main light switch ? Wondered if it could be related to the tow bar I fitted when I got the car, but this has been in place for years without issue. I checked the wiring of this and it all looks fine, and I'm not convinced as this shouldn't activate headlights.

Any guidance appreciated. Thanks
 

Tell

Full Member
Staff member
Moderator
2011 altea 1.6tdi eco with 90k.
Generally been a good car for past 6 years. Only previous problem was EGR valve failure which was expensive, just before diesel gate. At least diesel gate explained why I got nowhere near the claimed mpg (my previous car, clio dci exceeded combined mpg rating, even after 115k!)

Just had 2 problems, believed to be unrelated.
Firstly, I noticed the other day that the dipped headlights and side lights seem to be permanently on when driving. They come on when the ignition is turned on. Fortunately they go off when ignition is turned off so they don't flatten the battery. I don't have Xenons, so no daylight running mode (and tail lights shouldn't active in Daylight mode). Not critical but worried it might be forewarning of a more serious problem? Has anyone else experienced this?

Second problem was that a day or so later, the clutch pedal went to the floor and didn't disengage drive. Car effectively immobile - fortunately at home. I topped up the fluid with new DOT4 and pumped the pedal by hand, but could hear a hissing noise and pedal never regained usual feel, and fluid leaked onto the ground near the master cylinder. I found a local mobile mechanic who suspected a leak in or around the master cylinder. He was able to source a replacement and fit it within 24 hours, and I thought £250 was reasonable. Great service. However, I'm not impressed with VAG build quality.

Now back to the lights on problem. I've since had an occasional bulb failure warning message, but warning doesn't stay. As all lights work, it sounds more like a wiring or relay issue. Is there a lights relay as I can't find any info on one? Other options could be the main light switch ? Wondered if it could be related to the tow bar I fitted when I got the car, but this has been in place for years without issue. I checked the wiring of this and it all looks fine, and I'm not convinced as this shouldn't activate headlights.

Any guidance appreciated. Thanks

Had the lights one with the Altea I owned. Same, they came on without turning the switch. I booked it in and I was going to be charged a hefty diagnosis. Electrical control box they muttered over the phone. Anyhow it fixed itself after a few days. Think it was dampness. Never occurred again. I cancelled the booking. Also had one where the car was completely dead, would not turnover, although there was power. That fixed itself after 24 hours, they did look it over but found nothing. That fabled control box. Other than that it was a good reliable car for 12 years or so (apart from the AC fuse I use to pull to get it working again from time to time - my own "manual reset" - would pack up on hot or cold days - simple pulling the AC main fuse under the dash fixed it - evaded a hefty AC replacement cost).

Reckon there is an electrical control box that might be an issue with the lights.
 
Aug 1, 2020
2
0
Thanks for your response. It's been a few weeks now and lights are still on. I tried a replacement switch but no effect so maybe its the control box - but that sounds expensive. I can live with the daytime lights, provided the problem doesn't escalate.
Might try the AC reset - I'd given up with that. I thought it had a leak.
 

Tell

Full Member
Staff member
Moderator
Thanks for your response. It's been a few weeks now and lights are still on. I tried a replacement switch but no effect so maybe its the control box - but that sounds expensive. I can live with the daytime lights, provided the problem doesn't escalate.
Might try the AC reset - I'd given up with that. I thought it had a leak.

Oh you get the same AC issue. Never found anyone with that issue... just me. The heavy duty fuse of the AC. With ignission off, pull out for 5 seconds or so and push back... making sure you get it in the right hole. I did replace the fuse once or twice. They warp with heat. That was another question of whether a faulty fuse connection, so I changed them when the plastic warped the fuse. Spent twelve years doing that three times or so per year.

The other is probably the fabled control box on the lights.... the one the more reliable dealer muttered about but fixed itself.

(Ateca perfect, nothing idiosyncratic about that yet)
 
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