crafty1 Posted June 28, 2016 Report Share Posted June 28, 2016 72' 521 datsun can somebody post pictures on what wires connect to the alternator and what wires connect to the starter? thanks alot! i changed out my battery cables and I'm not sure where one of the wires that connects on the alternator side goes. datsun won't start up, interior lights come on, oil light came on once when turning the key, but now the light won't come on. No crank up. just wondering if my battery is "dead" or I missed something on the wiring. 1 Quote Link to comment
flatcat19 Posted June 28, 2016 Report Share Posted June 28, 2016 Battery (+) to big lug on starter Black with yellow stripe to spade terminal on starter. Thick white wire goes from big starter lug to lug on bottom of alt. Battery (-) goes to a bolt hole on cylinder head. 2 Quote Link to comment
KoHeartsGPA Posted June 28, 2016 Report Share Posted June 28, 2016 And make sure there's no paint between the ground (-) wire and bolt hole, bad ground can fry the wiring. 1 Quote Link to comment
datzenmike Posted June 28, 2016 Report Share Posted June 28, 2016 If the lights came on, but aren't now, then battery could be dead or loose/dirty battery cables on the battery OR the other ends on the starter or the ground on the head. Next might be the fuse box... blown fuse loose or corroded fuse or clip that holds them. Many owners have good results removing the fuse box and soaking in vinegar over night. I add lemon juice and table salt. Rinse well and dry. Vinegar and lemon juice contain acetic and citric acid which will clean and remove tarnish on the copper parts. 1 Quote Link to comment
HOGIE Posted June 28, 2016 Report Share Posted June 28, 2016 I would check if you have the yellow with black wire that goes to the oil pressure sender mixed up with the black with yellow wire that goes to the starter solenoid mixed up Then....... Tools to trouble shoot wiring 1) Multimeter (digital is better) 2) Test light ( not really necessary if you have ^^^) Use multimeter to check charge on battery If you have less than 12volts battery's dead If you have 12.5 than good battery and then check if you have power to the right 3 fuses ( both sides of the fuses) of the fuse block If the test light shows that there is power to the right 3 fuses then turn the key to ON and see if there is power to the left 3 fuses. Tape the test light to the black with yellow wire that goes to the starter solenoid, or have someone hold it, and turn key to start, or vise versa, and see if the light comes on. Also, if you have power on both sides of the left three fuses ten check if there is power to the (+) terminal on the coil 4 Quote Link to comment
crafty1 Posted June 28, 2016 Author Report Share Posted June 28, 2016 i multi metered the battery.. 10.5V. charging it now, 14.8, i don't think the cells are dead. maybe a 8 hour slow charge would bring it back to life. There was 1 wire that connect on the alternator side that was not connected.. I'm not sure if its supposed to be grounded or connected to something. I don't think I have the wires mixed on the starter side. but I could be wrong. I do better with actual pictures of your engine bay, then a schematic. thanks for all the help! 1 Quote Link to comment
datzenmike Posted June 28, 2016 Report Share Posted June 28, 2016 The alternator battery wire will have a rubber cover over the end and the terminal it goes to is insulated, the ground is just an open lug that bolts to the case to ground it. There is an obvious two wire plug that only goes on one way. 1 Quote Link to comment
banzai510(hainz) Posted June 28, 2016 Report Share Posted June 28, 2016 this is the simpliest ruck in the world how can you fuck this up. Ok white wire is the + output lug blk the ground case of the alternator the T connector. starter is blk/yelloe or in dought put the key to Start. the + batter usually has a white wire that goes the the fuse box also. Crafty take photos everythng with a camera before you take it apart. 14.8 v sounds good 521s most electrical proplems are corrossion issues at the fuse box or broken fuses 1 Quote Link to comment
KoHeartsGPA Posted June 29, 2016 Report Share Posted June 29, 2016 i multi metered the battery.. 10.5V. charging it now, 14.8, i don't think the cells are dead. maybe a 8 hour slow charge would bring it back to life. There was 1 wire that connect on the alternator side that was not connected.. I'm not sure if its supposed to be grounded or connected to something. I don't think I have the wires mixed on the starter side. but I could be wrong. I do better with actual pictures of your engine bay, then a schematic. thanks for all the help! Start by with a trip to local auto parts store and have them test that battery under load, that will eliminate this issue, try to do troubleshooting one step at a time, always begin with the easiest, test that battery, then move on to next issue. 1 Quote Link to comment
crafty1 Posted July 1, 2016 Author Report Share Posted July 1, 2016 this is the black wire i was referencing. its on a harness thats close by the alternator. Trying to figure out where that goes. 1 Quote Link to comment
bilzbobaggins Posted July 1, 2016 Report Share Posted July 1, 2016 Looks like the ground wire for the external regulator. It and the ground wire from the head should go on a stud on the back of the alternator. Fairly sure. Phone pics small 1 Quote Link to comment
datzenmike Posted July 1, 2016 Report Share Posted July 1, 2016 The alternator battery wire will have a rubber cover over the end and the terminal it goes to is insulated, the ground is just an open lug that bolts to the case to ground it. There is an obvious two wire plug that only goes on one way. 1 Quote Link to comment
banzai510(hainz) Posted July 2, 2016 Report Share Posted July 2, 2016 yes that open lug goes the the case ground of tha alternator bur look like something is screwed in to that already 2 Quote Link to comment
dat521gatherer Posted July 3, 2016 Report Share Posted July 3, 2016 Tell us where the black wire on the alt is going. Quote Link to comment
DanielC Posted July 3, 2016 Report Share Posted July 3, 2016 There should be two black wires connected to the alternator frame. One comes down from the negative battery cable, by the fuel pump. the second black wire, that goes into the wiring harness, goes to the voltage regulator, under one of the mounting screws for the voltage regulator. The alternator case must stay connected to the cab sheet metal, by the voltage regulator. If this wire is missing, the cab sheet metal tries to ground through the throttle cable. This destroys the cable, and may leave you with the throttle stuck open. 1 Quote Link to comment
dat521gatherer Posted July 3, 2016 Report Share Posted July 3, 2016 Daniel is correct. Most all 521's have had the original cables replaced but here is a original pic you can see it has the yellow stripe and the little that goes to the alt. So that other wire in your pic with the semi circle also goes on the alt case and comes down from behind the volt reg bolt/screw. Quote Link to comment
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