Quite often access to the High Voltage system can be challenging due to location of connections provided by the manufacturer. Even when we find a suitable point of access, we cannot see the physical contact points! So how do we know when your Multimeter is measuring for absence of voltage?

Most mechanics/technicians are in possession of an auto-ranging Multimeter. If you switch it to DC, you will notice the meters’ readout fluctuates with some millivolts being displayed. So, what’s happening here?

To explain. When we waggle the leads form the meter we are actually inducing/creating some electricity! Not a lot, but the Multimeter reads this.

So how can this phenomenon help us when checking for absence of voltage on the High Voltage system?

If we understand how the HV system is connected, with each component wired in parallel then when (and if) we go to measure for absence of voltage then we should be connecting to the large capacitors located in the Inverter/converter. If this is the case, then the capacitors will absorb the electrical current generated by the Multimeter leads. If this is the case then the Multimeter reading should not fluctuate, it should remain stable!