It is an electrical part mounted under the left front body/frame, not far from the alternator, and is wired to the alternator and/or harness in the area. It is difficult to see it under there. Is it a capacitor?? What does it do?

 

What car are you asking about?

 

I believe that is the alternator "dump module" yes it is a capacitor, if disconnecting it be careful, i can't remember the actual name.

 

Thanks 08,

It is called a "suppressor" in the wiring diagrams, connected directly to the generator. I don't fully understand its function, but I'm not going to mess with it! As a capacitor, it should be maintenance free anyway.

 

A supressor is just that - it supresses any electrical noise that could be generated. Remember the good old days when you heard a whine or a "tick tick tick" on your AM radio as your engine revved. This was electrical noise - the tick tick tick was from unsupressed ignition leads (a thing of the past - plugs now have built in supressors). The whine was electrical from the alternator (or on older cars the dynamo). This is removed by the supressor which is simply a capacitor. These can degrade with age and usually go open circuit (if it goes short circuit because it is connected to the +12V battery line it will blow the fuse). If it's open circuit you should be able to hear the whine on your radio. It's not just your radio that is affected - this noise will be present on all the supply lines. Most of the electronic modules should have their own supression built in so that they are not affected. How does it work? A capacitor will not allow a direct current to pass through it but will allow an alternating current to pass. Think of it like this - for a steady voltage it acts like an open circuit but for high frequency noise it acts like a short circuit. Because it is connected between the alternator output and ground it therfore short circuits the noise and removes it.

 

Very interesting! Thank you, man. Still learning new things about these cars! BTW RJ, this item is on the 6 powered cars, although I assume there's one somewhere under the 12's bonnet too. Maybe that's it on the right side under-panel, the generator is on the right, and very low on the V12. Very difficult to see what's all down there!