craig Posted October 12, 2010 Share Posted October 12, 2010 hi does anyone know where the alternator diode is on a 300tdi disco?im putting it in a 110. all wired up but alternator whistling, there a diode in the wiring diagram, does anyone know where? thanks Quote Link to comment Share on other sites More sharing options...
Puffernutter Posted October 12, 2010 Share Posted October 12, 2010 I'm not sure which diode you are referring to. I have both a Defender (200TDi) and Disco (300Tdi) and there are only three connections to the alternator in each case - (1) 12v to battery/starter motor (Out), (2) Dash Warning Lamp (Out) and (3) RPM pulses to tacho (if used). There is a rectifier block internal to the alternator, but nothing external that I can think of. Cheers Peter Quote Link to comment Share on other sites More sharing options...
craig Posted October 12, 2010 Author Share Posted October 12, 2010 hi thanks for replying on the old engine there was one thick one thin wire, sorted the thick one but when i connect the thin one to the original wire i get a whistling sound ( high pitched)but the charge light does go out. my brother who wired it all for me said i need a diode?? on the diagram there an alternator then wire then a diode then more wire?? i thought it would be part of the alternator but he seems to think it could be seperate?? im no electrickery expert as you can prob tell.... Quote Link to comment Share on other sites More sharing options...
crwoody Posted October 12, 2010 Share Posted October 12, 2010 I guess you mean "Diode (G182)" (bottom centre,) it will be there in order to block any reverse current flow when the ignition is off. I can't tell you where it would be physically, I would have assumed that it's built-in on some alternators, not easy to tell though, but without that wire connected to the alternator your battery will not charge. The "whistling" noise from the alternator could be due to heavy loading if the battery is badly discharged, I would suggest you put a voltmeter on the battery to check that it's not overcharging. Quote Link to comment Share on other sites More sharing options...
Puffernutter Posted October 12, 2010 Share Posted October 12, 2010 If you want a diode I can put one in the post to you. A 1N4001 (1A) will probably do, it's only feeding the coill until self excitation takes place. Cheers Peter Quote Link to comment Share on other sites More sharing options...
western Posted October 12, 2010 Share Posted October 12, 2010 hi thanks for replying on the old engine there was one thick one thin wire, sorted the thick one but when i connect the thin one to the original wire i get a whistling sound ( high pitched)but the charge light does go out. my brother who wired it all for me said i need a diode?? on the diagram there an alternator then wire then a diode then more wire?? i thought it would be part of the alternator but he seems to think it could be seperate?? im no electrickery expert as you can prob tell.... IIRC, that diode plus others are inside the main dash area wiring loom, not accessible unless you strip the dash & loom from the vehicle. Quote Link to comment Share on other sites More sharing options...
craig Posted October 12, 2010 Author Share Posted October 12, 2010 thanks all pete you have a pm Quote Link to comment Share on other sites More sharing options...
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