Auto Electrical problem no power anywhere after rebuild

[johnnyhillen]

Ive stripped and rebuild most of my 1998 nissan 200sx over the last number of years and will hopefully soon be finished but i have ran into an electrical problem and im an idiot when it comes to auto electrics and no idea how to read wiring diagrams

atm all the wiring is connected bar a section that only does the headlights. I connected up a charged battery to confirm everything was working and to get some lights on the dash for the first time in years but cannot get it to work. I first assumed it must be a grounding issue anf found a few small grounds that were not connected and connected them to the nearest bolt for now until i find where they are supposed to go. Any of the grounds from the loom for the headlights were grounded directly to the battery neg terminbal as that part of the loom was just sitting loose. the alternator bracket is off being powder coated so i connected up the alternator and ran a heavy cable from the housing to the engine block in lieu of the housing being bolted straight to the block. I have used an multimeter and checked continuity for all the earths and they are all good. the main earth that goes to the fuse box only connects with the ignition turned on all the rest seem to be permanent. When checking voltage Im getting slightly over 12v across the battery terminals and the same checking the positive against any earth.

with all that it still doesnt work. when i connect the terminals im not getting that tiny spark you would normally expect and no sign of power to anything else.

can anyone help

 

[PEG]

Hi bud,that earth or ground you mention,should not be switched,it will be permanent. The positive connections will be permanent,to the starter,alternator and fuse box,and there could be larger,fuse bridges to various other loads,and finally blade type fusing to other switched and permanent loads.

Check your polarity,then ensure continuity negative side from terminal to all engine,chassis and grounding points.

Then,follow positive side,from terminal to fuse box input,starter and alternator,if good,you should see 12V at ignition switch,and when on,at fuses and relays,etc.

Do not discount bad multi-plug connections,wrong connecting,old immobilisers coming live,or many other rebuild usuals...

You could do all the above,with a standard 12V test lamp,in less than 30 minutes

 

[johnnyhillen]

Thank you, I will try that today

 

[johnnyhillen]

i've narrowed the problem down to the alernator. when i bypass it and connect the + on the battery directly to the +input on the fusebox eveything works as expected.

can anyone shed any light on this. can the alternator be fixed rather than replaced

 

[Squid]

Are the connections the right way around on the alternator, you used to be able to get alternators rewound/rewound but at lot of the companies have closed down.