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1979-1993 & 94 Conv [Subscribe to Daily Digest] |
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, Tue, 26 Nov 2013 16:12:21
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CBS,
Justin was... slightly less right then usual (Justin, we're ok with this wording, aren't we?) on the batt light. The things there work the following way:
- on the one side of the alternator indicator light (which historically features the battery icon, not the alternator image) is the positive potential. In your case it comes from the ignition relay. The ignition relay gets this potential from the distribution box (the small black plastic box right by the battery). The ignition relay is toggled on by the #54 line on one side and the ground in the fusebox on the other.
- on the other side of the alternator indicator light is the VR unit (voltage regulator). And there are two connections inside the VR which go to that pin (where the wire from the batt light comes to): one goes to the rectifier unit (which gives it the positive potential generated by the alternator if it is generating the electricity; ovbiously, it gives nothing if the alternator isn't working either because it's stopped or because it's damn broken) and another goes to the 1st rotor brush. The 2nd rotor brush is always grounded (using the ground from the alternator body which gets the ground thru that famous alternator ground wire).
So, if you're still with me, we have the following picture:
- on the one side of the batt light is the positive voltage all the way while the ignition is on
- on the other side of the batt light we have the ground which comes from the alternator rotor
Right after the alternator gets excited (I wonder if alternator are lads or lassies?..) it starts making the positive voltage which appears on the rectifier - and you remember that lead I mentioned which goes from the rectifier to VR? - which appears on the VR pin. The alternator goes into self-feeding (actually, self-exciting, but there can be under-aged minors reading this) mode and no longer needs the positive voltage from the BATT light, having that positive voltage all around. Batt light goes off since it no longer has the ground potential - there must be the potential difference in the circuit to make the current and if there is no potential difference then there is no current.
Thanks for confirming you're reading me because I thought it wasn't the case after you started following advices from other knowledgeable TSN members who advised you to kick the tires and fill it up with the gas and immolate the virgin. I thought I was clear on my breakdown of your issue to make it obvious.
As for that ground point location - sorry, I am of no help here since I haven't been there personally and can only appeal to the Talmud. And that's what I did. Probably you need some more knowledgeable saaber lending a helping hand there like Jon (in a case he hasn't yet started changing an air filter because we all know it will end up with tranny overhaul and complete body restoration which means that Jon is a little bit busy there to answer our nubie requests).
Good luck,
Zig
posted by 188.134.4...
, Tue, 26 Nov 2013 14:43:44
, Tue, 26 Nov 2013 15:12:35, Tue, 26 Nov 2013 16:12:21, Mon, 2 Dec 2013 13:09:07
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