I've recently been suffering with the dreaded flickering lights syndrome. I've scanned for any fault codes and found nothing. Now I know in a lot of instances this is related to the steering angle sensor but this is usually accompanied by the steering light coming on on the dash. When I first got the car about 3 years ago I did occasionally get the steering light and a fault code logged but strangely this hasn't re-occured for about a year now - just kinda fixed itself!

I've been over the looms in the engine bay, checking for tightness and also voltage drop between the battery and alternator (both pos and earth), drop tested the battery as well and everything seems fine.

This morning I rigged up a voltmeter in the car which I could monitor whilst driving (took a feed off a batt pos on the fusebox). Generally whilst driving I get between 14.5v-14.6v, occassionally a little fluctuation but nothing significant. The only thing that did show up was that sometimes when I start the engine the alternator doesn't switch in (voltage around 12v) until the revs exceed 1800rpm. Other times I can start it and I get 14.5v immediately.

This has got me flummoxed and could easily get expensive! I haven't totally ruled out the steering sensor (£75) but neither am I certain of the alternator (can get a recon Bosch for £151). Incidently, the present alternator and battery are only 2.5 years old and have probably only done 18k miles.

Any ideas?:confused:

Any ideas?:confused:

...I guess not then:(.

Looks like I'll have to start randomly throwing money at it - new steering sensor here I come!

the electric PAS takes so much current to make it work that you will get the flickering lights , even mine do when its dark and i've got ful lock on , as you've not got any fault codes , i wouldn't start changing stuff just for the sake of it

as for the alternator not charging , that is probably normal if it has got a smart charging system , it wont charge the battery unless the battery actually needs charging or there is a electrical system drawing a large current

Thanks for the comments, but the headlight flickering can be quite severe at times and can occur at any time regardless of engine speed or steering input. It's actually an embarresment driving in traffic as it can appear I'm flashing the lights at other road users!

Forgot to mention, another symptom I've experiencd a couple of times last week is during a full lock manouver the pump can be heard to go into a 'spasm'. Not the normal continuous whining sound but more a 'whoop, whoop, whoop' as though it's either not getting enough current/voltage or it's not sure exactly what it's doing!

Think I'll give it another scan on vagcom tomorrow - surely it's got to log a fault whith these symptoms?

Done a few more miles with the voltmeter attatched today and now have a clearer picture of what's going on.

After a cold start the volts drop from a resting figure of about 12.5v to about 11.8v. After around 30 seconds of normal driving the voltage regulator decides to play ball and brinsg the voltage upto 14.5v. This is then maintained regardless of electrical load or engine speed. Then, at random the volts will start to fluctuate between about 13.5v-14.6v - this is when the light start to flicker. This fluctuating phase can last from a few second upto many minutes.

Again, no faults logged on the ECU!

I still do not know whether these symptoms are down to a dodgy voltage regulator/alternator or if some component (eg power steering pump) is randomly drawing much more than its fair share of current and the voltage reg is struggling to keep up?

I'm now leaning towards the alternator. Has no-one else really not got any thoughts or advice on this?

sounds alternator ish, I wonder if you can pull the power steering pump fuse and repeat the test, or do a similar test with car stationary, eg not using steering??

sounds alternator ish, I wonder if you can pull the power steering pump fuse and repeat the test, or do a similar test with car stationary, eg not using steering??

Thanks, I did wonder about isolating the PAS pump but definitly don't fancy driving it without - it aint fun!

Maybe as you suggest, try running at idle with PAS fuse removed - trouble is, the intermitent nature of the voltage fluctuation could mean waiting at idle for some time!

I've been doing a bit of reading up on the voltage regulator and have found conflicting information on the specified running voltage. Haynes say it should be no more than 14v, but I've read a few references that state it can be closer to 14.5v:confused:.

UPDATE... just realized my battery/alternator light doesn't come on when I switch on the ignition! What might this mean and why no fault codes?

I reckon alternator. It won't leave any codes unless battery voltage drops very low.

First check the warning light & control unit (and the cable for it)- if you measure with a multimeter on a DC voltage range from the warning light cable (blue) at the alternator to ground with the ignition on, do you see 11-14v?. Many alternators won't start to charge until higher than normal revs if the lamp is blown or disconnected: the lamp feed is used to excite the windings, and at higher revs they self-exclite. I notice that things have moved on and there's a control unit of some sort connected into what would have been the warning lamp circuit- anyone know what or where that is?

As you're seeing 14V or so when running, the alternator is charging but it sounds like it's not doing so all the time.

Sounds alternatory to me too.

I had the PAS yaw sensor thing (which can be had off Ebay for £40 ;)) and it would usually begin with the light flickering really badly, then all of a sudden it would stop, the PAS light would come on, and PAS would be dead. Also had a fault code too.

Due to this not being the case with you, I would look to a dodgy alternator.

I reckon alternator. It won't leave any codes unless battery voltage drops very low.

First check the warning light (and the cable for it). Many alternators won't start to charge until higher than normal revs if the lamp is blown or disconnected: the lamp feed is used to excite the windings, and at higher revs they self-exclite.

As you're seeing 14V or so, the alternator is charging but it sounds like it's not doing so all the time.

I think you've hit the nail on the head! I've been doing quite a bit of searching and just found this thread http://www.briskoda.net/forums/fabia/fabia-electrical-help-needed/35460/.

The unlit alternator light was the final clue - especially as you say, "the lamp feed is used to excite the windings".

I'll get under the car tomorrow and... fingers crossed!

The unlit alternator light was the final clue - especially as you say, "the lamp feed is used to excite the windings".

I've seen it before . On an old Escort diesel van, similar effect- it would only charge once revs went up.

FINAL UPDATE - PROBLEM FIXED:thumbup:

Total cost of repair = £0.00!

It was indeed a break in the blue (D+) wire which runs from the 2 pin plug on the alternator to the ECU. Apparently this is a known issue on the Fabia and the break nearly always occurs near a connector at the front of the gearbox (or sometimes the connector itself corrodes). It's a rather awkward location and can only be seen looking up from beneath the car with the undertray removed. On examination, the broken wire was immediately evident.

Anyway, thanks to all those that took the time to offer up suggestions and advice.

Cool

Glad you fixed it.

A good result.