truck dies when headlights are on

[banzai510(hainz)]

if your rig is OVERCHARGING

it will ruin that battery also.

 

ck the voltage again and se if its really 15.6 like you said.

Datsunaholic is correct. a overchaged battery will bulge and usually cook the acid out ruining the engine bay paint. Or in my case my chromed valve cover.

My case was a Bad Made in USA mechanical voltage regulator(NAPA, Neihoff)

[]2eDeYe]

I think you need to get an ohm meter and check your headlight circuit and your charging circuits to find out where the problem is before replacing any more parts.

It could be something as simple as a loose battery cable as Hainz has already mentioned...

 

I also still think you could have installed a gm (saturn) alternator for less $ and problems than you've already experienced.

It is cheaper, more powerful and more reliable than the 30+ year old system that is in the truck now.

 

...listen to these guys on the overcharging issue as well, bad stuff that.

[lynchfourtwenty]

i replaced it with stock parts because i knew what i was doing.. i dont know how to modify stuff very well yet and i didnt want to screw anything up... non of the batterys have had bulges.. but the posts are a brownish.. like maybe they've gotten too hot.. when i change the battery i will see what happens... that 15.6 was before the voltage regulator got change.. my friend took it to auto zone but he didnt remember none of the crap the guy told him so ya.. but the autozone guy did say the battery was toast..

[ggzilla]

do you think 15.6volts is a little on the high side??

Yes, that's too high. Nissan specification is no more than 15 volts. See Voltage Regulator. Datsun B110 and 620 use the same Voltage Regulator, but none are higher than 15V. Lead-acid car batteries shouldn't be given more volts.

[lynchfourtwenty]

suprised the guy didnt say anything ya know?? maybe he's an idiot...

[yello620]

Has this problem been resolved yet? Hos is your sentra doing?

 

Jason

[lynchfourtwenty]

i gotta get a battery, gonna get one maybe friday.. the new sentra's ok.. havent swapped anything other then the deck lid

[kiznook]

saw anthony riding in the red sentra sometime last week...random

[lynchfourtwenty]

yea he borrows whatevers up for grabs..

[lynchfourtwenty]

ok so i finally put a new battery in the truck.... THE F-ING CHARGE LIGHT IS STILL ON!!!!!!!! ok this is driving me crazy.. new batt new alt new volt reg. im stumped.. hey does anyone have a pic of the fuse box cover??? cause i noticed if i unplug the bottom left one the charge light goes off.. but i think the whole cluster goes out..

[ggzilla]

Yes, pulling the fuse causes the light to go out, but doesn't fix the problem. You are on the wrong track.

 

To test if the alternator is working, use a voltage meter. 13.5-15.0 volts is right. More or less is wrong.

[lynchfourtwenty]

i've takin it to auto zone twice and had two different guys run tests an they both said the alt checked out fine.. as well as the battery.. an there was no "draw" either.. i think that 15.6 was wrong it was in the 14's... i think im going to change the battery cables.. i think they're toast anyways.. im sure everyone would agree if they saw them.. the coppers dark brown.. theres blueish white battery acid growing in them.. ect ect... i just noticed this also otherwise i'd have mentioned it b4

[datzenmike]

Something is fucked... can you borrow a good alt then a reg and try them? The red dash light has the ignition key supplying 12 volts from the battery to it on one side and the alt. output on the other. As long as the alt. 'puts out' there is 12 volts on both sides of the light and it can't light up. As soon as there is a difference in voltage on one side (alt or reg failure), current flows and it lights.

[yello620]

So, can he figure out which side of the light has power and which does not to help diagnose this. Just causethe light is on does not mean that the alternator is not charging and the voltage regulator is not working. There could be a system short between the key and the light that would cause the light to come on, or there could be a short between the voltage regulator and the light that would also cause the light to come on.

 

Jason

[lynchfourtwenty]

ALL I KNOW IS IM STUMPED lol .. im gonna atleast try to replace the battery cables and stuff.. wont hurt.. needs it anyways

[kiznook]

I'm gonna guess that yellow620 is on the right track and that it's somewhere in the dash/instrument cluster. Especially knowing the history of that truck, dash, and wiring

[lynchfourtwenty]

its possible.. at this point im not ruling anything out thats for sure.. im just tryin to do the easist first.. an the bat cables really do need replaced.. an someone mentioned that before which is why i looked into it.. i guess it wouldnt hurt to take the cluster out an the after market gauges an stereo ect. and maybe clean up the wiring a bit.. but if i do that i want to use actual new wire.. instead of extra datsun wire.. lol replacing 30 year old with 30 year old wire is like bringin sand to the beach

[datzenmike]

Now if your alt and reg. test good, then there might be a broken, loose, corroded or missing wire between :

1/ The wire harness and the regulator.

2? The regulator and the alternator. (there are only two wires between the reg. and the alt. itself)

3? The wire harness and the alternator.

 

First disconnect the reg.

 

1

Test the White/Blue wire on the engine harness side... it must have 12 volts when you turn the key on (ign.) Without this it's like driving with the key off and there's no charge.

Now test the White wire, it should read 12 volts battery at all times.

Now test that the Black wire goes to ground.

 

2

Use a circuit continuity tester to test the two wires between the reg. and the alt. Disconnect the regulator and the White/Black wire and the Yellow wire on the alternator. Test that they are solid and continuous.

 

3

Now test for 12 volts at the White/Red alt. wire.

And that the Black alt. wire goes to ground.

 

 

In the regulator there is a relay that grounds the charge light to turn it on when the key is on and the motor not running (no charge). When there is charge, the relay is held open and the light stays off. The regulator needs 12 volts, a switched 12 volts from the ignition, a ground, and two wires from the alternator to regulate it's charge rate in addition to the dash charge light indicator wire.

The alternator requires a connection to 12 volts, a ground, and the two wires to the regulator, so it knows how much to charge.

 

I have the internally IC regulated alternator so I had to look up and learn this stuff.:D

[nismopu]

My guess is the number 3 that mike listed!

[5casey1dimer0]

i am having a very, very similar prob with my 510. i even went about replacing my reg, batt, and alt too. same thing happens. when the lights are on, drains the batterie. just before this happened, i got rear ended, it came back from the bodyshop and my flashers stopped working, the fuse for them kept blowing. so i had a family friend mechanic come and take a look. he did multible tests and said its most likly a short in my wiring to the flashers. i dont do wiring, so its in the shop now getting that fixed. luckily i dont have to pay for all this as the lady that hit me's insurance is gettin the bill. my guess is that its a short somewhere in your wiring to something like the flashers, reverse lights, fuel gauge, something little.

[lynchfourtwenty]

i fixed the problem ages ago.. bad alt + some wires that need cleaned up an its ok..