datzenmike Posted August 10, 2019 Report Share Posted August 10, 2019 If this was charging before the alternator was changed and then after changing the alternator there was no charge.... what part do you think would be the cause of this?????????????? The old working regulator or the new but unknown alternator???????? Where's the old regulator? I never throw away old parts unless definitely proven to be bad. Quote Link to comment
Eddie Cantina Posted August 10, 2019 Author Report Share Posted August 10, 2019 Old regulator is gone. Parts store wanted it for the warranty. I know the old alternator was bad cuz I got it tested. Failed all across the board. So now I guess I’m just stuck with shit alternators and regulators.... Quote Link to comment
Eddie Cantina Posted August 10, 2019 Author Report Share Posted August 10, 2019 (edited) Maybe just screw these parts stores. Im gonna go on rock auto and buy a NEW alternator and regulator. Edited August 10, 2019 by Eddie Cantina Quote Link to comment
wayno Posted August 10, 2019 Report Share Posted August 10, 2019 Your not stuck, but if you cannot get it to work then you have 2 choices(choices in my world), pay someone else to get it working with what you have bought so far as they likely are not all bad parts, or move on to a internally regulated alternator like I did, I drove around with a half on ignition light on for a few years as it was charging as I had the auto parts store guy tested it while idling in the parking lot, the guy was scratching head head as the light was half on, it was full on with the lights on, I drove it that way till it was not charging anymore, when my radio started cutting out I realized it was not charging anymore. Personally I would not buy anymore alternators or regulators, something is likely smoked in the wiring harness or like I mentioned before a connection is not making a connection, I don't know if 620s had fusible links, but you need to figure out why the alternator is not energizing, one of your wires in that tee that plugs into the back of the alternator is likely the issue. Quote Link to comment
Eddie Cantina Posted August 10, 2019 Author Report Share Posted August 10, 2019 (edited) Well. Lookin at that t. I just cut the plug and put spades on those two wires . Yellow and a black and white one. Yellow goes to a fusible link with the yellow coming out of the heater relay. Black and white goes directly to the pigtail to the regulator. Black wire on back or alternator position “e” got to negative ground. White and red wire goes to a fusible link to black wire going into cab to the fuse box. Which from there goes to ignition key. Again. Maybe a dumb question. But could the ignition switch be the problem? Motor starts and everything works. Just not getting 14+ volts!!! Edited August 10, 2019 by Eddie Cantina Quote Link to comment
Eddie Cantina Posted August 10, 2019 Author Report Share Posted August 10, 2019 Also. I ripped the dash out and physically looked at every wire in that harness. Everything looks great. Of course I can’t see inside the coating so who knows.... Quote Link to comment
thisismatt Posted August 10, 2019 Report Share Posted August 10, 2019 Ok, since you cut off the tee connector and just have spades, the leg of the tee should be the white with black stripe and this goes to your charge light. Pull it and charge light should no longer work. The top of the tee should be the yellow and this goes to +12v. Disconnect it and with key-on this wire should be reading +12v to ground. This is your "sense" wire for the alt to determine how much voltage to put out. Quote Link to comment
wayno Posted August 10, 2019 Report Share Posted August 10, 2019 (edited) The yellow wire coming out of the heater relay is supposed to go to the alternator and the regulator(N post), I see no fusible link in the yellow wire in the wiring diagram, the black/white one also goes to the regulator, the main black goes to ground and the regulator in the wiring diagram, the big white-red wire goes to a fusible link that goes to the battery and it also goes to the fuse block. I looked at a 1974 Datsun 620 wiring harness on another forum, it would not let me copy it to paste it here. Also when you don't use the plastic tee plug, the top of the tee can sag or get bent down and then the 2 wires can touch which will likely mess things up also. Edited August 10, 2019 by wayno Quote Link to comment
Eddie Cantina Posted August 10, 2019 Author Report Share Posted August 10, 2019 How can I post a video on here? Quote Link to comment
Eddie Cantina Posted August 10, 2019 Author Report Share Posted August 10, 2019 Confirmed. My wiring is correct. To clarify, when I say fusible link, it’s just the ends of the yellow come into a cluster which appears to have been soldered and a black vinyl cap/sleeve put over it. Quote Link to comment
Eddie Cantina Posted August 10, 2019 Author Report Share Posted August 10, 2019 (edited) Ok.... soooo.... pulled black and white which would be going to “N” on alternator, light stays on. Test yellow wire “F” (positive lead on multi tester to spade) negative lead on multi tester to ground. Nothing. Test white and black wire in similar fashion, 12v.... also, with both yellow, and black/white wire disconnected charge light is still on.... riddle me that batman............ Edited August 10, 2019 by Eddie Cantina Quote Link to comment
thisismatt Posted August 10, 2019 Report Share Posted August 10, 2019 5 hours ago, Eddie Cantina said: Ok.... soooo.... pulled black and white which would be going to “N” on alternator, light stays on. Test yellow wire “F” (positive lead on multi tester to spade) negative lead on multi tester to ground. Nothing. Test white and black wire in similar fashion, 12v.... also, with both yellow, and black/white wire disconnected charge light is still on.... riddle me that batman............ Yellow goes to N, White w/Black stripe goes to F. Quote Link to comment
Eddie Cantina Posted August 10, 2019 Author Report Share Posted August 10, 2019 But that’s not what the wiring diagram indicates. (To be honest, I tried it on another regulator and it smoked a little bit. Pulled the regulator off and the coil in the back looked like it got hot ) Quote Link to comment
wayno Posted August 10, 2019 Report Share Posted August 10, 2019 This is what the wiring diagram I looked at said for a 1974 Datsun 620, yellow wire coming from the heater relay goes to both the "N" on the regulator and "F" on the alternator, the white/black line wire goes from the "N" on the alternator straight to the "F" on the regulator. This seems goofy to me, seems like "F" should go to "F" and "N" to "N" but that is not what the wiring diagram says. Quote Link to comment
Eddie Cantina Posted August 10, 2019 Author Report Share Posted August 10, 2019 (edited) http://tinypic.com/r/34zbxx1/9 sorry. Not the best at uploading. So what are we saying here, F goes to N and N goes to F?!?! When I tried this the regulator smoked a bit...never tested voltage because I was too scared to leave it running after it smoked.... Edited August 10, 2019 by Eddie Cantina Quote Link to comment
Eddie Cantina Posted August 10, 2019 Author Report Share Posted August 10, 2019 Also, again, when I tested yellow I got no volts. Black and white had +12v. With key on. Explanation of that? Quote Link to comment
wayno Posted August 10, 2019 Report Share Posted August 10, 2019 This is the wiring diagram I am looking at in the link below, it will not let me copy it. https://redirect.viglink.com/?format=go&jsonp=vglnk_156546246024814&key=519c853d0f59fbaa5d68e228c32940c4&libId=jz5vwqwb010229ac000DAaz18lqze&loc=https%3A%2F%2Fnicoclub.com%2Farchives%2Fdatsun-pickup-wiring-diagrams-for-320-520-521-620-720.html&v=1&opt=true&out=http%3A%2F%2Fwww.datsunforum.com%2FDatsun_Wiring_Diagrams%2FDatsun%20620%20Pickups%2FDatsun_620_Pickup_Wiring_Diagram_1974.pdf&ref=https%3A%2F%2Fwww.google.com%2F&title=Datsun Pickup Wiring Diagrams for 320 %2F 520 %2F 521 %2F 620 %2F 720&txt=<strong>1974 Datsun 620 Pickup Wiring Diagram<%2Fstrong> Quote Link to comment
wayno Posted August 10, 2019 Report Share Posted August 10, 2019 I have had regulators smoke the moment I plugged them in and turned the key on, it is why I mentioned before that I have never had a new regulator work out of the box I bought from a auto parts store, but I have had them work when I got a used one from a wrecking yard. I don't have anything using a regulator anymore except my 320 and my 1967 Datsun Roadster, everything else I own has an internally regulated alternator, I just had too many issues with externally regulated alternators. Quote Link to comment
datzenmike Posted August 10, 2019 Report Share Posted August 10, 2019 12 hours ago, Eddie Cantina said: Confirmed. My wiring is correct. To clarify, when I say fusible link, it’s just the ends of the yellow come into a cluster which appears to have been soldered and a black vinyl cap/sleeve put over it. This means someone was in here before you and was messing with it. Did this ever charge properly before you changed the alternator and regulator????? Quote Link to comment
Eddie Cantina Posted August 10, 2019 Author Report Share Posted August 10, 2019 Yes. Charging was fine Quote Link to comment
Eddie Cantina Posted August 10, 2019 Author Report Share Posted August 10, 2019 (edited) I can’t see how anyone was ever in it. My pops has had it since 76. Got it off in old lady in Long Beach California. Here’s a photo of that yellow. I had to peel back the original electrical tape around the harness to find it. http://tinypic.com/r/28s973n/9 Edited August 10, 2019 by Eddie Cantina Quote Link to comment
datzenmike Posted August 10, 2019 Report Share Posted August 10, 2019 Then the wiring harness and ignition is fine and if only the regulator and the alternator were changed it has to be those two. The fact you had to turn in the old regulator under warranty means it wasn't an original Nissan one also. Quote Link to comment
datzenmike Posted August 10, 2019 Report Share Posted August 10, 2019 Nissan would never do it this way. Quote Link to comment
Eddie Cantina Posted August 10, 2019 Author Report Share Posted August 10, 2019 There’s three more places like this. One by the radiator for headlights. Quote Link to comment
Eddie Cantina Posted August 10, 2019 Author Report Share Posted August 10, 2019 (edited) So, swapped the yellow and black/white wire in back of alternator. Charge light with key on lights. Start truck, turns off. Reading with volt meter fluctuates around 15-17v ..... too much Edited August 10, 2019 by Eddie Cantina Quote Link to comment
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