Got voltage dropping and the fans randomly kicking in at the same time. They start blowing and switch back off immediately.
With fans running randomly or continously i would expect darlington unit. However, with the power off the fans do not run. Also the switch does still operate the fan speed.
With the drop in voltage the lights also dim.
Seems like some short appearing, but no clue as of yet where to look.
Battery is fully charged and does charge when running.

 

A failed or failing Darlington doesn't always mean that the fans will run with the ignition off. One symptom is one of the fans running fast even on Posn 1, and also the fan pulsing momentarily when the ignition is on and the fans turned off. I have this situation on the right-hand fan and am waiting to pull it down and replace the Darlington.

Paul

 

With the fan switch in the off position, doesn't the fan give a momentary pulse when you turn the ignition 'ON'? I thought the Delanair MK3 system did that.