Good day everyone,

My first time here. Trust you are all fine and doing well. I have a Volvo V40, 2000 model. I got the car as a non runner. The previous owner failed to get the dual cams (valve timing) sorted out, not sure how the cams should go, and using the marks also does not help. Anyways, working with the cams, I tried starting the car only to my horror encountered a short on one of the injectors. My eye caught a quick flash/spark and after securing the wires the engine won't turn over. Further to this, when I turn the ignition on, the flasher relay clicks very fast. The indicators (bulbs) do not illuminate. However, when I select right or left turn signal with ignition on, then the indicator bulbs illuminate. So, the flasher circuit works fine, the only strange thing is when no direction is selected the flasher unit clicks fast. Would this indicate a blown ECU? All fuses had been verified inside and engine compartment.

 

An LED can flicker because of vibrations from road travel, and the car is picking up on this... And then as soon as the vibrations are gone, the flicker stops, If you get curious about it, move tail light signals around... Right to left and left to right and travel around for a week... Do the same for the fronts... When the rapid signaling follows a specific changed bulb you caught the failing bulb and can change it

 

The most common cause is a blown or failing bulb, as the flasher relay is designed to click faster when it detects reduced electrical load. Corroded bulb holders, poor earth connections, or damaged wiring can also trigger fast clicking by increasing resistance in the circuit. In some cases, fitting LED bulbs without the correct resistor or an LED-compatible flasher unit will cause the same symptom.

 

+1 on checking bulbs. the flasher relay uses a capacitor to toggle the relay and its charge time is dependent on the load (ie bulb) resistance. Dead bulb or a LED replacement will make the on/off cycle faster.