AO Silver Member
Join Date: Mar 2003
Re: Ongoing Bulb Failure Warning Light!
Yes and all the problems were the rev counter.
What happens with the blown diode is the power leaks to earth. Mostly this is through the rear off side lamp. The lamp is obviously connected back to the the warning lamp in the rev counter. The power simply goes in reverse, through the filament, out to the lamp earth point. Any other devices in the rear of the car load the earth and the path then changes.
This is the classic "all the lights on" when braking in other cars. This is caused by a rusty earth so any lit bulb just sends its power through its own earth back in to the earth of another bulb and then on to the live feed and out to a good earth.