26-07-14, 06:11 PM
What you most likely have is copper corrosion or burning of the 30 amp contacts within the the Starter relay itself creating high resistance in the circuit. It gives exactly the symptoms you describe.
Measuring the voltage across it is not an effective test, you would need to check the current flow and since that can be 30 amps no ordinary meter could be used to test it.
You could try testing the resistance across the contacts by disconnecting the two large cables to the battery and starter motor.
Connect the test leads to those connection on the relay, set meter to Ohms, if reading is above zero when starter button is pressed, change the relay.
You can buy a brand new starter relay for £20.
Measuring the voltage across it is not an effective test, you would need to check the current flow and since that can be 30 amps no ordinary meter could be used to test it.
You could try testing the resistance across the contacts by disconnecting the two large cables to the battery and starter motor.
Connect the test leads to those connection on the relay, set meter to Ohms, if reading is above zero when starter button is pressed, change the relay.
You can buy a brand new starter relay for £20.