Lights Flicker.

jmd · Unread post by **jmd** » 05 Nov 2009, 00:56

Any ideas where to start in attenpting to cure the above problem. Continous flicker on my lights, worse on tickover. Alternator was repaired a few weeks ago & no problem immediately afterwards. With engine switched off no problem, and problem seems to disappear at 2000 RPM & above. Any suggestions would be appreciated. Car is a 2.0 Ltr 1997CC, Hdi

Unread post by **Paul-R** » 05 Nov 2009, 09:15

Faulty earth connection between engine and body?

Still don't know what car it is though.

jmd · Unread post by **jmd** » 05 Nov 2009, 09:51

Sorry Paul. It's an Xantia 2.0Ltr Hdi

HDI · Unread post by **HDI** » 05 Nov 2009, 10:57

You need to check the voltage across the battery when the fault is present.
If it's high it's a good bet it's the alternator , if low it's likely to be an earth or other wiring issue.

Xantidote · Unread post by **Xantidote** » 05 Nov 2009, 14:23

I go along with HDI's suggestion to monitor the voltage at the battery, and then maybe between battery +ve and body, in case problem at earth terminal, though we don't get the crude on the terminals like we did in the old days. Paul's picked up on possible poor earth to body

Aa a slim chance, could be a partially fractured cable between alternator and battery, but unlikely. My money's still on the alternator. Why was it repaired in the first place?

Have you a spare alternator you could fit as a substitute?

Cheers - Martin

jmd · Unread post by **jmd** » 13 Nov 2009, 01:55

Bearings in need of changing, hence the repairs to the alternator. It has improved somewhat -with the sort of weather we have had here in the past week I didn't check it out yet.

Xantidote · Unread post by **Xantidote** » 13 Nov 2009, 11:03

Maybe in replacing the bearings, the brushes haven't been refitted correctly and aren't happy in their guides, or (coincidentally) they're pretty well worn/knacked, in which case, why weren't they renewed at the same time?

Unless the drive belt was overtight, bearing replacement suggests the alternator must have done a lot of miles.

Martin

jmd · Unread post by **jmd** » 13 Nov 2009, 11:12

120,000 Miles covered & the belt had been overtightened, although serviced in a main dealership throughout it's life

Unread post by **Peter.N.** » 13 Nov 2009, 12:11

Still sounds like an alternator fault, you really need an analogue voltmeter across the battery, you should then be able to see the needle moving at low revs if that's where the fault is.

jmd · Unread post by **jmd** » 14 Nov 2009, 18:05

Checked out my earth connections to-day. Cleaned all connections at the side of the battery, which are bolted to the metal surface. A lot of dirty greasy connections there, which I cleaned with white spirits & re-coated with Vaseline ( Petrolium Jelly). Just took the car for a run & everything seems fine, in fact the lights appear somewhat brighter. Prior to carrying out the job the voltage across the battery terminals was ranging from 14.3 - 14.6 volts. Didn't check it after doing the cleaning job. Thanks to everyone for your suggestions.

Xantidote · Unread post by **Xantidote** » 14 Nov 2009, 19:27

Well, that voltage seems OK to me. I assume the voltage variation was as the battery became charged after start up, rather than continually ranging around between these figures. Checked mine recently after engine running 4-5 minutes, and it gave 14.35-14.4 volts at battery.

Brighter lights, and no flickering - job done!