Mmmmm been thinking, C5 Headlamp flicker

h2ocooler · Unread post by **h2ocooler** » 26 Mar 2009, 13:21

Ok so my brain has been working overtime on the flickering headlights.
My thoughts are that the hydraulic pump is now electric and will draw a large current on startup BUT that would make the lights dim not go brighter, now when the pump turns and the headlights etc are on the alternator will kick up its output (amps and volts) to cope however when the pump turns off the alternator will take a split second to react and will continue to pump the amps and increased volts making the headlamps go brighter then back.
On the cars that the lights dim it could be the battery is a little weak and cant supply enough power for the pump and headlamps etc hence the lights dim for a split second till the alternator ups it output.

Just my thoughts and welcome any comments or addiotional thoughts.
Rob

Citroenmad · Unread post by **Citroenmad** » 26 Mar 2009, 14:10

Both of our C5s do it, i think they all do?

The fact is the battery is always going to be weaker than the alternator, so there will be a slight flicker when the pump first cuts in?

steelcityuk · Unread post by **steelcityuk** » 26 Mar 2009, 14:16

Generally when the battery gets weak on a C5 it let's you know by playing up in various and unconnected ways. I've heard that if the battery gauge is half way or less with no electrical load then expect problems. I can't verify this personally mind.

Steve.