How to check the ballast resistor wire

[Klaus Schlueter]

Hi all,

this question belongs to my thread "All of a sudden...." which I will update soon with my findings.

In an old post I found how to test if the ballast wire is fitted:

-take all the wires off from the negative terminal
-earth the negative terminal
-switch the ignition on
-measure the voltage at the coil plus terminal. It should read about 6 V.
If it reads about 12 V no ballast is fitted.
Is that correct? And is my drawing correct?

[marshman]

Yes that is correct. If the ballast wire is there and the correct resistance then you will get around 6V across the coil. If no ballast is fitted then you will get 12V ( essentially battery voltage).

NOTE: Allow a bit of tolerance on the voltages as it is all related to the actual battery voltage and the actual resistance of your coil.

Roger

[Klaus Schlueter]

Many thanks Roger. I'll check it today.
Klaus

[wilf]

Don't leave it "on" for too long.

[Klaus Schlueter]

Thanks Wilf. Good to know.
Klaus