Battery light coming on intermittently

[Lobster]

Ok R4 hive mind, a little help please!

1985 F6, 1108. Battery light intermittently coming on. Doesn't seem to do it for the first ten miles of driving then comes on occasionally, then a bit more. No real pattern as to when it comes on, can be in light traffic or when using some throttle. Doesn't do it at idle. Any ideas? Can't see any loose wires or anything along those lines.

I should be going to Voiture Amour in Derbyshire on Sunday, question is, will I make it and should I see if I have a second hand alternator kicking about and take it with me?

 

[Andy McGhee]

Ok R4 hive mind, a little help please!

1985 F6, 1108. Battery light intermittently coming on. Doesn't seem to do it for the first ten miles of driving then comes on occasionally, then a bit more. No real pattern as to when it comes on, can be in light traffic or when using some throttle. Doesn't do it at idle. Any ideas? Can't see any loose wires or anything along those lines.

I should be going to Voiture Amour in Derbyshire on Sunday, question is, will I make it and should I see if I have a second hand alternator kicking about and take it with me?

How's the drive belt tension?

 

[Lobster]

How's the drive belt tension?

Tight - little bit of movement if you press on it but not slack at all.

 

[jcarruthers2]

Hi

Do you have access to a multimeter? If so you could run a battery and alternator test.

Can you hear a whirring sound coming from the alternator (worn bearing)?

If you do have a spare alternator, no harm in taking it along with you.

 

[malcolm]

It's unusual to be intermittent and not happen at idle. Well worth measuring the battery voltage when running to see if you get 13.5V or so, and if possible tape the meter to the bonnet and see if it changes when the light comes on. That would pick up any loss of function of the alternator or regulator.

Could be a short to earth on one of the little wires going to the top of the alternator. Can't remember which one but one of them should be 12V when the engine is running and that turns off the warning light. Haynes should have a good enough wiring diagram to check that.

 

[Lobster]

Hi

Do you have access to a multimeter? If so you could run a battery and alternator test.

Can you hear a whirring sound coming from the alternator (worn bearing)?

If you do have a spare alternator, no harm in taking it along with you.

I'm off to buy a multimeter in the morning. I'll see if I've got a spare alternator and have a look at that. I think firstly though I'll clean and remove all the wiring to the alternator, see if that makes any difference.

 

[Lobster]

Quick update…. Took all the connections off the alternator, cleaned and refitted. Decided to have a good look at the belt and found it has seen better days, and whilst I can’t see why it would cause me the issue I have, I’ll change it in the morning anyway. Then we’ll see how we go!

 

[André4Renaults]

Bloody hell, that belt HAS seen better days....! Change that straight away & see if it improves things before doing anything drastic!