Back Probing

This is a practice to be able to get a reading from a back of a plug specially in the situation where we need this plug connected but also want to get a reading while its connected to its counter part .... We do this process so that we don't damage terminals, connectors and also wires.
To do this we use a sewing pin to gently insert it to the back of the plug so there is a contact with metal so we can obtain a reading.

1. Turn the multimeter on and put the setting to it would read Ohms (resistance)
O/L : is the result when the leads not in contact with each other , O/L stands for over load which confirms that we have an open circuit and the resistance between the leads are too high for our multimeter to show hence O/L.

2. Obtaining Ohms reading with leads connected.
0.5 Ohms which tells us the internal reasistance of the Ohms meter and the leads... we need to take this resistance out of any resistance we measure with this meter so we could have an accurate reading .

3. I used a plug which had one side of the pulg and the wire still attached so I back probed the plug and measured the resistance from the plug to the end of the wire which was 1.1 ohms
so 1.1 -0.5(internal resistance)= 0.6 ohms which is the correct resistance readings

I tired to back prob my distibutor so I could get a reading but the plastic around the wire was solid due to years of extereme heat .
I back probed Toyota soarer O2 sensor so I can get a reading after it was warmed up and working , real easy because it was single wire so 1 lead to the O2 sensor and the other to the -negative battery terminal (0.7 votls)