lynchfourtwenty Posted January 8, 2008 Report Share Posted January 8, 2008 i changed my alt. and the belt.. im pretty sure its the internal regulated type.. it will run with out a battery just fine.. but after a few minutes of the head lights bein on it completely drains the battery and the truck will die while driving.. im stumped please help! Quote Link to comment
Pacific coast Datsun Posted January 8, 2008 Report Share Posted January 8, 2008 Im not an electric genius but could a bad headlight relay be causing this? Could be a bad alt too,have it tested to see if it's putting out enough amps. Quote Link to comment
lynchfourtwenty Posted January 8, 2008 Author Report Share Posted January 8, 2008 i just put a brand new alt in.. when i first turned the headlights on everything was bright as could be.. 5 mins later dead as a door nail.. i do have a bad headlight that i gotta tap every now and then to make it work.. where would i find the actual relays.. this is a new problem altho the headlight has been broke a while.. one of the prongs on the back is busted... i changed the alt and belt thinkin that was the problem.. but its doin it same thing.. thanks bro.. ok so what am i lookin for as far as relays?? Quote Link to comment
Pacific coast Datsun Posted January 8, 2008 Report Share Posted January 8, 2008 The relays are on the core support on either side of the radiator. Ive seen NEW alt's be bad right from the start..get it running & go to Auto zone & have it tested. Quote Link to comment
lynchfourtwenty Posted January 8, 2008 Author Report Share Posted January 8, 2008 ok sounds good thanks :) Quote Link to comment
yello620 Posted January 8, 2008 Report Share Posted January 8, 2008 This might seem dumb, but could the headlight that needs tapped be shorting out and draining the battery? Try disconecting that headlight and see what happens. Or try dosconnecting all four headlights at the bulbs and the turn the headlight switch on and see if that kills the battery, if it does it kinda eliminates the bulbs being a problem. I would suspect that your Alternator is not working very good. I have gotten two reman's that were crap, always get the lifetime warranty. Jason Quote Link to comment
lynchfourtwenty Posted January 8, 2008 Author Report Share Posted January 8, 2008 yea i got the warrenty.. i will try that tomorrow and see what happens hopefully i can figure it out soon ;) thanks guys Quote Link to comment
datsunfish Posted January 8, 2008 Report Share Posted January 8, 2008 Disconnect the broken light.A bad relay can send the wrong signal to the wrong places.Your relay controls the power to the head lights only.Get a test light.The red wire is power from the light switch.The red and black is power to low beam.The red and white power to highbeams and red and yellow a ground shutoff from the high beam switch that when shutoff sends power through the relay to high beams. I had to re wire a ton of stuff in my 620 recently.If your engine dies when you turn on the lights I suspect a short that draws all power down.Put the test light on + side of the battery and check for ground on your power leads to the lights.everything on mine showed ground and I had to rewire it all.Melted wires under dash. Quote Link to comment
lynchfourtwenty Posted January 8, 2008 Author Report Share Posted January 8, 2008 i hate wiring.. :( hopefully its not nasty out tomorrow so i can check it out Quote Link to comment
banzai510(hainz) Posted January 8, 2008 Report Share Posted January 8, 2008 if everthing was OK before the alternator change why would it be the headlights lot of alternator are bad from the factory(from the cheap autoparts stores) put a test light in between the neg side battery and the battery cable. if light is ON then there is a drain. disconnected the red wht wire to the alt if goes away then the alt is bad. or do as datsunfisch says and disconnect stuff unteill it goes away. Quote Link to comment
SHADY280 Posted January 8, 2008 Report Share Posted January 8, 2008 its your battery, most ppl overlook the battery, charge it and have it load tested, or at least check you connections and make sure they are tight and clean. even new batteries can be screwed. the battery is your reserve amperage, and headlights will kill a truck if the poor little alternator has nothing to help it. Quote Link to comment
lynchfourtwenty Posted January 9, 2008 Author Report Share Posted January 9, 2008 the truck was fine.. until one day it died while driving (at night) i replaced the alt and belt thinkin that was the problem.. when i first started it back up all the lights were bright as could be.. the battery isnt very old either.. when i get time i will experament.. its just so rainy.. :( Quote Link to comment
Cruzn620 Posted January 9, 2008 Report Share Posted January 9, 2008 go to autozone and just have them test the system, they will test the battery and the alternator for free. it has saved me a lot of time in the past Quote Link to comment
lynchfourtwenty Posted January 9, 2008 Author Report Share Posted January 9, 2008 they come out to the vehicle.. i dont have to undo anything? Quote Link to comment
yello620 Posted January 9, 2008 Report Share Posted January 9, 2008 Yes, my local autozone(newberg) has a tester that is mounted on a rollaround cart. He just rolls it out to the truck and does most of the work. He made all of the connections, all i had to do was start the motor when asked and the hold the RPM at about 2k until he asked me to shut it off. FREE Jason Quote Link to comment
lynchfourtwenty Posted January 9, 2008 Author Report Share Posted January 9, 2008 well then thats what i'll do if unpluggin the broken headlight dont fix it Quote Link to comment
datsunfish Posted January 9, 2008 Report Share Posted January 9, 2008 I think that anyone who drives a 30 year old Datsun should at least own the necessary tools to figure things out.Get a multi meter at sears for $25.Get a test light.Have someone load test your battery or replace it if you havnt. Not trying to be an ass but I am realizing that with knowledge comes....TOOLS!Tools are great.You really cant daily drive a beat up datto without something going wrong eventually so be prepared!:cool: Quote Link to comment
DanielC Posted January 9, 2008 Report Share Posted January 9, 2008 Like it was said, get a voltmeter, and check your battery voltage. A fully charged battery should have a little over 12 volts with the engine off, and recently ran. When you start the car, the voltage should go up to around 14 to 14.5 volts, and if you turn on the headlights, the voltage might drop a little, but it should stay above 14, at the battery. You can get a voltmeter at Sears, Radio Shack, Home Depot. Quote Link to comment
dat521gatherer Posted January 9, 2008 Report Share Posted January 9, 2008 hainz gets an a+ for the negitive cable test light trick.:thumbsup::thumbsup::thumbsup: and if your out somewhere and dont have a test light you can tap the negitive terminal on the post and if you hear or see a spark then you have a short somewhere. start unhooking shit until it stops. Quote Link to comment
lynchfourtwenty Posted January 24, 2008 Author Report Share Posted January 24, 2008 ok so i took it to auto zone and the guy did a bunch of tests on the truck.. said the alt is charing at max 15.6 or something like that.. the battery had like 12.4 volts or something.. umm he did a test on it to see if there was a draw somewhere and couldnt find anything.. i disconnected the bad head light and i have driven the truck around a bit.. the first few times it was normal.. the last few times the Charge light has been on.. when i first noticed it i could rev it and get it to go away for a second but then it just comes back on.. OH i've changed the battery since my last post also.. the truck hasnt died on me but i havent had the head lights on while driving yet.. or the radio for that matter.. im stumped.. new alt, new belt, new batt.. guy said there was no draw anywhere.. any more ideas fellas?? Quote Link to comment
DISLEXICDIME Posted January 24, 2008 Report Share Posted January 24, 2008 is the regulater internal or external for the alt Quote Link to comment
lynchfourtwenty Posted January 24, 2008 Author Report Share Posted January 24, 2008 pretty dang sure its internal.. or atleast thats what i've been told what could i look for that may help me tell the diff? Quote Link to comment
yello620 Posted January 24, 2008 Report Share Posted January 24, 2008 The ALT light going on and off as you rev it is suggesting a bad voltage regulator. I dont know how to tell the difference by internet description. Havent owned a datsun alternator in about 10 years. Jason Quote Link to comment
lynchfourtwenty Posted January 24, 2008 Author Report Share Posted January 24, 2008 it has a L shaped plugin.. a black wire looks like a ground.. a white with red stripe wire if i remember correctly Quote Link to comment
ggzilla Posted January 24, 2008 Report Share Posted January 24, 2008 Ha! I'm having a very similar problem with my Datsun right now. It charges fine during the day. But when headlights are on at night, the battery discharges...one night the ALT light came on but never before or since. Alternator voltage is perfect (14 volts) and battery seems OK... Quote Link to comment
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