2002 Ford Fiesta strange electrical issue

Once the car has been started, neither the indicators, heater fan, or electric windows work for at least 5 minutes; the lamp in the air- recirculation switch is glowing dimly at the same time, although if you operate the switch i.e. switch on air recirculation, it glows with normal brightness . Once a certain amount of time has elapsed, the lamp goes out, and the other circuits are live once again. I have checked the common earth point at the base of the drivers' 'A' Pillar, and had to replace one of the ignition relays in the fuse board on the drivers' side, as it was showing heat damage. I have also had to replace the heater control valve. This problem only started when I had to replace the battery a few months ago, and it is worse when the weather is cold and damp.