weird electrical fault

[The real Apache]

Renault 19 of considerable vintage but in good nick, bombing along the M25 when the alternator/battery light starts flashing spasmodically, sometimes bright, sometimes dull. I noticed that it stopped when I put on the indicators....and when I put the sidelights/mains on. I had the fan on a low setting all the while so it would suggest a circuit issue rather than a load one.

Anyone seen this before?

[Dog Star]

Sounds like a bad earth to me.

[Petrolhead_Rich]

bad earth, check around the front headlights/indicators/alternator/blowers!!!