ruparts Posted February 25, 2011 Share Posted February 25, 2011 (edited) hi, i need some help on my 84 wagon, i was on a trip overnight, suddenly the lights went dim and the guage showed discharge. i pulled over and turned off the lights and the guage went back up to charge a little over midway. i waited till daylight and continued my trip, for several days now the battery has not run down and after 1000 miles it still starts the motor and runs fine ,, BUT if i turn on the lights they come on dim and it shows a major discharge , same with the blower fan and cooling fan, runs but seems slow and the guage shows discharge. now the fun part, the alternator shows to be putting out full 13.8 voltage , using my multi meter, (even with lights on ) and its one of the nissan 90 amp that i had tested at the auto store and told it was fine. any idea whats up , where all does the main wire from the alt to battery run ? can i use a bypass direct batt + to alt connection wire to eliminate the harness one while keeping the two small ones as they are ? the battery has 13.4 v just sitting , it shows 14.4 v with motor running , and it shows 14.4 v with lights on (all 4) headlights on and the heater blower on high, so it must be getting charge, or am i missing something ? ideas , comments, help?? thank's Edited February 25, 2011 by ruparts Link to comment Share on other sites More sharing options...
ferox Posted February 25, 2011 Share Posted February 25, 2011 (edited) can i use a bypass direct batt + to alt connection wire to eliminate the harness one while keeping the two small ones as they are ? First you should replace your fusible links, but yes you can upgrade the wiring. You will want to find the factory crimp where the main wire from the alt. connects to the harness so you can cut the old wire out of the circuit. On my '84 I found it near the charcoal canister. On my '81 I found it near the battery. For the "two small ones" you will probably want to upgrade your field sensor wire, but you can use the stock dash light wire. Make sure you run the new main wire to the fusible link box and replace the connection from the fusible link box to the battery as well. Edited February 25, 2011 by ferox more info Link to comment Share on other sites More sharing options...
ruparts Posted February 25, 2011 Author Share Posted February 25, 2011 Yes you can upgrade the wiring. You will want to find the factory crimp where the main wire from the alt. connects to the harness. On my '84 I found it near the charcoal canister. On my '81 I found it near the battery. For the "two small ones" you will probably want to upgrade your field sensor wire, but you can use the stock dash light wire. Hi, thanks , first i am wondering if that main wire could or would cause the problem i'm having if it is bad . it is in the harness so i don't know where all it goes. if it could, then can i just run a big wire directly from batt pos to alt main terminal , and leave the 2 little ones alone ? thanks Link to comment Share on other sites More sharing options...
naru Posted February 25, 2011 Share Posted February 25, 2011 Different batteries have different voltages,but,"13.4 v just sitting " sounds too high to me.Have another meter? Headlights and blower use seperate fusible links. Check voltage to the headlight relays by measuring voltage on fuse#1.(powered side) Check voltage from the headlight relays by measuring voltage at fuses 9 and 10. Check voltage supply to the blower by measuring at any of fuses 4-8. I would check the ground under the far left side of the dash by putting a voltmeter between it and battery negative w/everything running.Should be 0V. Hydrometer or load test the battery too. Good luck. Link to comment Share on other sites More sharing options...
ferox Posted February 25, 2011 Share Posted February 25, 2011 Checking and cleaning all of the main connections, fusible link connections, and grounds can make a surprising difference too. I just did the battery connections on mine the other day and it made a noticeable difference. I would go through Naru's diagnostic suggestions, but if you want to run new wire then make sure you do it right. Run it through the fusible link, not straight to the battery (+). Replacing the field sensor wire is really easy and can just be a fused wire to battery (+). If you are going to do it, it's probably best to learn how that all works or you could accidentally create a fire hazard, and there are plenty of multimeterings that can be done to narrow down your problem before surgery...but it's a nice upgrade nonetheless. Link to comment Share on other sites More sharing options...
Cougar Posted February 25, 2011 Share Posted February 25, 2011 Going from what you said the voltages are at the battery the charging circuit is working fine. The trouble you are having is due to a wiring problem between the battery and the wiring to the accessories of the car. It could be a bad connection in the ignition switch area so check the connector to it and look for signs of burning. It may help to check the voltages getting to the dash fuses. If they are all low then you need to look under the hood. There may be a problem with one of the fusible link connections as Ferox wisely noted. Make sure they are clean and making a snug fit. Check the chassis ground to the battery also. Link to comment Share on other sites More sharing options...
gadberry Posted March 1, 2011 Share Posted March 1, 2011 CHECK THE GROUND FROM THE BATTERY TO THE BLOCK... I have been chasing similar gremlins on my '81 Wagon GL which is a lil different than your wagon, in that i have an external voltage regulator. I've replaced the alternator, battery and the voltage regulator (now's the appropriate time to giggle) and my last part to replace will be the negative cable to the block.. which appeared to be partly seized back when i was working on this beast 5hrs from home, in the woods... so hopefully that 7 buck section of black wire will solve my bouncy voltage gauge... i'll confirm when I get around to changing it out. but i'll buy ya a coffee if it ain't the ground wire.. i'm feeling generous tonight, I guess. I hope that's it! cheerio, Link to comment Share on other sites More sharing options...
ruparts Posted March 2, 2011 Author Share Posted March 2, 2011 (edited) Hi, thanks to everyone for their help, I think naru found the problem. ESPECIALLY Thank You naru, you said to check the ground under the far left side of the dash, not being sure what wire or exactly where , i dug in, and by the time i got the fuse box and bracket down, i saw a 6" black wire with an eyelet coming from the main harness. it may have been attached under one of the screws , i don't know , but after putting it securely to ground on the bulkhead !!! all is well again, and , with the 90 amp nissan alternator i can run the lights and heater at idle and no discharge , i like it a lot. IMO the nissan upgrade is well worth the time and money , and it's easy , also i made a jumper from the suby connector to the nissan plug and now it's easy to just unplug it for replacement or service. gadberry, it was a ground but not that one, too bad i could use a cup now. Thanks to all for your help Edited March 2, 2011 by ruparts Link to comment Share on other sites More sharing options...
Recommended Posts
Please sign in to comment
You will be able to leave a comment after signing in
Sign In Now