30-08-2022, 08:03 AM
Hi Colin
The common wiring shared between the Headlights and the Trafficators (negative earth) is:
1 Main thick starter cable from Battery positive to Starter Motor Switch
2 Link from Starter Motor Switch to Ammeter
3 Ammeter to input of PLC switch
4 Earth link from Body/Chassis back to Battery negative
If the starter turns over OK you can discount No 1 above. I suggest you check the rest. Number 4 can give problems with anything that earths via the body/chassis, but it won't affect ignition, starter motor or generator as these all earth directly back to the battery via the thick starter negative cable.
It's important when chasing this type of effect to generally keep the negative end of your meter fixed on one point, e.g. the earthy side of the battery. You are then always measuring relative to the same place.
The exception is when you are particularly interested in the voltage drop across a particular component, in which case put the probes either side of that component and see what the voltage drop is when carrying current. For example to test No 4 above, connect one probe to battery negative and the other to the body, then turn on the headlights.
The common wiring shared between the Headlights and the Trafficators (negative earth) is:
1 Main thick starter cable from Battery positive to Starter Motor Switch
2 Link from Starter Motor Switch to Ammeter
3 Ammeter to input of PLC switch
4 Earth link from Body/Chassis back to Battery negative
If the starter turns over OK you can discount No 1 above. I suggest you check the rest. Number 4 can give problems with anything that earths via the body/chassis, but it won't affect ignition, starter motor or generator as these all earth directly back to the battery via the thick starter negative cable.
It's important when chasing this type of effect to generally keep the negative end of your meter fixed on one point, e.g. the earthy side of the battery. You are then always measuring relative to the same place.
The exception is when you are particularly interested in the voltage drop across a particular component, in which case put the probes either side of that component and see what the voltage drop is when carrying current. For example to test No 4 above, connect one probe to battery negative and the other to the body, then turn on the headlights.