Ignition light flashes very regulary over 20 mph

[eisdielenbiker]

Hi,
today I encountered a strange phenomenom with my 71 coupe. Sometimes the ignition light flashes in the manner of a direction indicator. This occurs only at higher speeds than 20 mph. It immediately stops flashing if i brake even if i simultaneously keep up the constant speed above 20 mph by the throttle pedal. When i revv the engine in parking idle position the light remains absolutely dark. No rain or oily stuff is involved with the engine bay. The belts ar OK. Does the light indicate any other subject than malfunctioning charging ? Brake fluid or automatic transmission e.g.? Any ideas besides checking the wiring contacts around that cylindrical control unit near the fuse box ? That's what i have read in the archives.
Thanks
Mark

[Phil Nottingham]

When it flashes again watch the ammeter - if it does not waver it is the cylindical warning light control can as you srmised This is non-repairable.

If it does not it could be a number of things some cheap some not so so try that and report back

[eisdielenbiker]

Yesterday I cleaned the ground contact point from rust and debris. Furthermore I cleaned the 3 contacts of the cylindrical device too. I took off all connections of the alternator control box finding no problems and reconnected them. This morning i checked the voltage at the battery in the boot: 13,0 Volts engine off, 14,0 to 14,4 Volts engine idling after a short drive around the block to warm up. And today on a 60 miles drive no flashing occured again. Just once there was a single glimpse of the red light. I will look for the alternator brushes soon although the voltages measured are ok i think. Btw. my ammeter wavers always strongly around the 0-mark. If i switch on heater fan it becomes even worse. The estimated mean value is in +range however. I guess i should also look for more corroded ground connections etc.

[Phil Nottingham]

Connections aside it points to worn brushes - after that the 4TR regulator. The 6RA field relay may also be past it.

The ammeter needle should stay still!