charge light won't go out

[wayno]

Hi there ratsun folk, I seem to have a problem, my alternators bearings went out a while back so I put another alt. in and all was well for a little while, then it started over charging the battery, all the while the charge light in the dash has not been on except when turning on the ignition before starting, I put a amp gauge under the hood and seen that it was putting out almost 30 amps all the time, went to the auto parts store and bought a new voltage regulator, put it in and started the engine and the charge light was half on for a few seconds and then went very bright, unfortunatly I have not been able to get it to turn off since, I put the old voltage regulator back in, light is still on, put two differant alternators in and no change, the light is still on. I had a feeling that something wasn't right, so I got my volt meter out and checked the voltage without the truck running, it was about 12 1/2 volts, started the truck, and it reads about 14 volts, hmmm. I took the truck to the auto parts store and asked them to check it, Ryan went out to the truck with the meter and he checked the voltage with the engine not running, he told me the battery was fully charged, then with it running and it was charging fine, I tried to get the headlights on but it took to long(finicky fuse block sometimes) and the timer ran out on the meter before I had them working(I don't drive this truck at night much), but he seemed to think that the alt. was charging fine, then I asked him what's with the freaking light, he said "it's on?", I said yep, It won't turn off, he took a look, and said he didn't know why it was on. I have a 1971 datsun 521 with a basicly stock wiring harness, what could make the light not go out while it is charging fine. wayno

[nismo dr]

sometimes i have to smack my dash to turn the light out

[bilzbobaggins]

sometimes i have to smack my dash to turn the light out

 

 

ditto...

 

jeff

[Ooph!]

I'm having this same issue with my 99 Ford. I looked at the wiring diagram for the 521 and didn't see it but usually there is a diode (or some other device) in the instrument cluster .

When the voltage level goes above a certain level the light goes out.

It appears you have wiring issues so this seems logical to me.

[datzenmike]

Running voltage of 14 is good. 30amp isn't really a good indication of anything. Everything appears normal so clean the battery terminals and the other ends at the starter and the ground on the head. Be sure there is a solid ground strap from the block to the body or the neg terminal on the battery to the body sheet metal. Check the wires on the alt are tight and making good contact. Do the same with the regulator and check that it has a good ground connection with the body sheet metal. Won't hurt to do this even if it does not help after all the truck is 40 years old.

[wayno]

I am begining to think that the battery went bad and that was why the alt. was pumping 30 amps into it, trying to charge it up. I put that battery on the charger and after a day it still was trying to charge it, I don't understand it because I have a smart charger that won't charge bad batterys. So I changed the voltage regulator for no reason I suspect and now have probems. The truck has been beat to death for over 10 years and has so much blowby and leaks from the blowby that I went threw 2 quarts of oil on a 300 mile trip, the wipers have so much play in them that I need to be going over 40 mph to get a full swipe/pass, the valve on #3 cly. is out of adjustment(no more threads left) as the valve is sinking into the head, if I put my foot into it to much the clutch starts to slip sometimes, the stupid fuel and temp gauge go up and down so much that I always carry a full 5 gallon gas can in case it runs out of gas cause I can't tell how much it has, and to top it all off, I can't run the heater fan on full because a couple months ago it threw something and now the fan blade is so far out of balance that it shakes the whole cab, and I really mean the whole cab. I have been planing to take the truck down this winter and rebuild everything but have been so busy working(it is the work truck), that I just keep patching it till the work stops coming in, it's charging so I think i'll just remove the light till I can get to the above metioned probems, i'll just add the light to the list. Maybe i'll do the GM conversion I seen on this forum the other day. Enough ranting. :lol: wayno

[izzo]

damn wayno, you have got some good use out of that pickup!

 

Ive had my 720 for 2 years now, thats the longest ive ever owned a vehicle. I've also done a shit ton of work to it, theres not much original parts left on it. Thing is very depndable!

 

Good luck with it

[datzenmike]

I am begining to think that the battery went bad and that was why the alt. was pumping 30 amps into it, trying to charge it up. I put that battery on the charger and after a day it still was trying to charge it, I don't understand it because I have a smart charger that won't charge bad batterys. So I changed the voltage regulator for no reason I suspect and now have probems. The truck has been beat to death for over 10 years and has so much blowby and leaks from the blowby that I went threw 2 quarts of oil on a 300 mile trip, the wipers have so much play in them that I need to be going over 40 mph to get a full swipe/pass, the valve on #3 cly. is out of adjustment(no more threads left) as the valve is sinking into the head, if I put my foot into it to much the clutch starts to slip sometimes, the stupid fuel and temp gauge go up and down so much that I always carry a full 5 gallon gas can in case it runs out of gas cause I can't tell how much it has, and to top it all off, I can't run the heater fan on full because a couple months ago it threw something and now the fan blade is so far out of balance that it shakes the whole cab, and I really mean the whole cab. I have been planing to take the truck down this winter and rebuild everything but have been so busy working(it is the work truck), that I just keep patching it till the work stops coming in, it's charging so I think i'll just remove the light till I can get to the above metioned probems, i'll just add the light to the list. Maybe i'll do the GM conversion I seen on this forum the other day. Enough ranting. :lol: wayno

 

I had an old 521 back in the '70s just like that. Drove the shit out of it and only fixed enough to keep going.

 

Take the adjusting nut off and grind it down thinner so you can turn it down some more. :lol:

[wayno]

I am going to resurrect this thread, as it basicly is the same issue.

I posted this below in my 521 work truck thread, but it is likely an electrical issue of some kind.

 

 

 

OK guys, something is wrong with this truck electrically, I have issues with the starters and the alternators, the alt. light has been on slightly(very dim) for years now, I finally gave up on externally regulated alts. last year because the light was on all the time, yet it was charging, so when it did go bad I didn't know it, so I made jumper wires and put an internally regulated alt. on, and the damned light was still on, but very dim.

This morning while going down the freeway something gave up, and the light got very bright, since I have a volt meter now I can see what was going on sort of, right now when the engine is running(idle) the volt meter needle slightly jumps up and down from 12v to 11v, it's like the blinker is on, but it is not on, when I do turn the blinker on it really jumps up and down.

The only time I seen the light this bright was when I tried putting a US made voltage regulator(points type) on last year just before I went to the internally regulated type.

Over the last several years I also have issues with starters, they either over a period of time run slower and slower till they won't turn anymore in or out of the truck with or without help from a hammer, and the solenoid starts the clicking thing and won't turn the engine over, I am back to the clicking thing this time, I can use a big screwdriver and jump the two main posts and start it no problem, so I am thinking about using a ford type starter relay and just connecting it to the starter motor post instead of the solenoid post, this is like the 3rd or forth starter this year.

I need to know what is causing these issues, it likely is a related issue as there is a main wire connecting the two, from the alt. output to the starter solenoid, and then the main wire to the battery.

My battery does not have a drain, it stays charged up, but the starters and alternators are going bad, and that damned ignition light has been slightly on for several years, it has been easy to see at night, but you would have to get close to see it during the day till today.

What is going on with this truck, I need to drive it everyday during the week, I do have 2 delco remy one wire alternators in the shed, but they are bigger, and I will have to fab a mount at the very least, but the fact is, there isn't a lot of room down there, and I will have to remove the oil filter minimum to get that type of alternator in there to mount it.

There has to be a reason why the starters and alts. are going bad and the alt. light is on slightly all the time.

 

Can anyone tell me what's going on?

 

BTW, this starter only lasted a week before starting to have issues, this one is a Z24 starter.

[ggzilla]

the alt. light has been on slightly(very dim) for years now

Not too uncommon. I had that happen for about a year. If it always happens it usually means the altenrator is partially bad.

 

put an internally regulated alt. on, and the damned light was still on, but very dim.

Ah, so it is a different cause. Might have a short in the wiring harness.

 

To test this theory, pull the T-connector out of the alternator and with KEY OFF, check the Lamp connector ohms to ground. It should be infinite. Instead you might be seeing 200k ohms or something a small draw.

 

 

volt meter needle slightly jumps up and down from 12v to 11v

Shorting wire?

 

I am back to the [starter] clicking thing

Dirty connections for sure. Not the starter, not with multiple starters.

 

there is a main wire connecting the two, from the alt. output to the starter solenoid, and then the main wire to the battery.

Actually that wire is the 12V feed from the POS battery cable which is connected to the starter. The common issue might be a less than perfect connection. When I change starters I always grind/file/sand the terminal ends to bright metal. All the wires and the nuts & washers. Then coat with battery spray (or clean oil).

[ggzilla]

On second thought, a more likely cause of the CHG light dimly glowing is a voltage drop in the wire for the CHG llght circuit.

[Laecaon]

Hmm. For the starter, you state you can jump the solenoid posts and it starts reliably. Well then wouldnt this mean a problem with the solenoid? The Ford solenoid is very nice. I would say there is a problem either with ground, or your signal wire from the key. Another issue might be battery cables. My car had intermittent starter issues where it would just click, but a new battery cable fixed that. I assume the old cable had too much resistance and the voltage drop across that and the solenoid was too much for the starter, but oddly enough I could still jump the starter solenoid and have it start.

 

Alternator is interesting. I found this in my quest to understand a charge light:

If the light gets brighter with RPM, and the voltage is over 15 - 15.5 then the regulator is fried. Since the regulator is inside the alternator on the 720s, that means you either need a new alternator or would have to replace the internal regulator (doable, I've done it, but might as well change brushes and inspect bearings at that point). I had one go bad on the freeway- jumped to nearly 20V. I quickly turned EVERYTHING on (heater, headlights) and it fell to 14.5V, but turn off accessories and it badly wanted to overcharge. Fortunately I make a habit of checking gauges and caught it before the battery exploded.

 

If it's a dim glow, but the voltage is in the normal range then it's at overload. Since the 720 alternator can power EVERYTHING in the truck simultaneously (unless you have massive baja lights, a huge amplifier, or some other massive electrical load), the light shouldn't glow. If the voltage is charging but low (above 12.3V but below 13.7v) then the alternator is getting tired, usually brushes but could be something else.

[ggzilla]

yes, it could be an IGN switch problem. Or wiring to switch. A guy earlier this year had a loose connection on the back of the switch.

 

Ford external starter solenoid is a hack. Thousands of Datsuns work fine without it.

[wayno]

It will only click, the solenoid is working, it is jamming the gear into the flywheel, but no power is routed to the starter motor, but if I take a big screwdriver and jump the two main posts(the solenoid post to the starter motor post), it starts fine, so it is not the cables, there is plenty of power going though the cable to turn the starter motor.

I just can't have that bad of luck, having that many starters that work fine for one week to 3 months and then go bad, this last Z24 starter looked almost new, it seems to work half the time when it is cold(sits overnight), but when warmed up, forget it, push the truck(roll down hill), or use the screwdriver.

I am going to pull the alternator again in the next hour and take both of them to be tested.

 

I am not sure what the word "infinite" means ggzilla, as I really don't know how to use an ohm meter the way you are talking about, I use the ohm type meters to test for voltage(12V), other than that I have not a clue what infinite means, if I were to guess, I would think that if I set the meter on ohms, and did what you described, it would peg the meter, is this correct???

It turns out there are 3 differant settings for ohms, RX1, RX10, and RX100, which one should be used?

There is only one set of numbers that go from 0 to 250, I am assuming that these are to ones to look at.

Here are the differant settings I have for ohms, RX1 reads about 60ohms, RX10 reads 170ohms, and RX100 reads about 235ohms, what do these readings mean?

[wayno]

Both the alternators tested good???

[ggzilla]

the solenoid is working, it is jamming the gear into the flywheel, but no power is routed to the starter motor

That's part of the solenoid, yes. The more important function of a starter solenoid is as a high-power relay. When the gear kicks out, the internal copper disc kicks up and connects the two large posts. Many starters fail this way, the copper get burnt. You can unsolder the terminals and clean the copper disc.

 

I worked on a car where the owner reported it kept eating starters. It was because oil was leaking right over the starter and contaminating it. Fixed the oil leak and the new starter lasted.

 

 

What you have is a multi-meter. Ohmmeter only checks resistance. Voltmeter only checks voltage. Multi-meter has both.

 

RX1 reads about 60ohms, RX10 reads 170ohms, and RX100 reads about 235ohms, what do these readings mean?

60 x 1 = 60 ohms

170 x 10 = 1700 ohms

235 x 100 = 23500 ohms

 

 

But that particular ohmmeter only goes up to x100 range so it won't measure a 100,000 ohm small leak. Another way to test it is by voltage drop or test light.

[datzenmike]

 

I am not sure what the word "infinite" means ggzilla, as I really don't know how to use an ohm meter the way you are talking about, I use the ohm type meters to test for voltage(12V), other than that I have not a clue what infinite means, if I were to guess, I would think that if I set the meter on ohms, and did what you described, it would peg the meter, is this correct???

It turns out there are 3 differant settings for ohms, RX1, RX10, and RX100, which one should be used?

There is only one set of numbers that go from 0 to 250, I am assuming that these are to ones to look at.

Here are the differant settings I have for ohms, RX1 reads about 60ohms, RX10 reads 170ohms, and RX100 reads about 235ohms, what do these readings mean?

 

 

Infinite resistance would be a wire with a break in it where there is no electrical connection whatever.

 

When measuring resistance start with the highest scale RX100. if the meter barely moves try a lower setting RX10 should be 10 times more sensitive and RX10 ten times more sensitive. Say you have a mystery resistance that is 5 ohm. On the RX100 it will barely move the meter. The green number one is 100ohms so the meter will only show 1/20th of that. On the 10X it will read .5 (or half the green one which represents 10 ohms) and on the X1 it will read green 5 ohms.

 

If your mystery resistance was 2,000 ohms the 1X would be off the scale to the left between 500ohms and infinite. On the 10X scale it would be between 100 and 500 and still not easy to read except to guess at. But on the 100X scale where green one is 100, the green10 is 1,000 then the meter would read 20 or 20X100 or 2,000 ohms..

[wayno]

ggzilla wrote in an earlier post,

To test this theory, pull the T-connector out of the alternator and with KEY OFF, check the Lamp connector ohms to ground. It should be infinite. Instead you might be seeing 200k ohms or something a small draw.

 

These are the readings I got,

 

RX1 reads about 60ohms, RX10 reads 170ohms, and RX100 reads about 235ohms

 

Do these readings mean that the alt. is good or bad?

[Laecaon]

ggzilla wrote in an earlier post,

To test this theory, pull the T-connector out of the alternator and with KEY OFF, check the Lamp connector ohms to ground. It should be infinite. Instead you might be seeing 200k ohms or something a small draw.

 

These are the readings I got,

 

RX1 reads about 60ohms, RX10 reads 170ohms, and RX100 reads about 235ohms

 

Do these readings mean that the alt. is good or bad?

 

It seems to me you are reading the black numbers. Read the Green numbers when checking Resistance (oHms)

 

 

But those numbers translated to oHms, is like 16oHms.

 

This is when a digital MM is nice.

[ggzilla]

Yes, an "auto-ranging" digital is easier to use. A few digital ohmmeters still have a range selector.

 

The green scale on Wayne's photo is for Ohms (omega symbol Ω)

 

That particular test is not testing the alternator. Pull the T-connector out to test the wiring circuit from the connector (not the terminal).

With KEY OFF, because with key on the wire is live and the ohmmeter won't read correctly.

[wayno]

Yes, an "auto-ranging" digital is easier to use. A few digital ohmmeters still have a range selector.

 

The green scale on Wayne's photo is for Ohms (omega symbol Ω)

 

That particular test is not testing the alternator. Pull the T-connector out to test the wiring circuit.

With KEY OFF, because with key on the wire is live and the ohmmeter won't read correctly.

 

I tested it on the floor, it was not even in the truck, was this a mistake?

[Laecaon]

 

 

I tested it on the floor, it was not even in the truck, was this a mistake?

 

I think he meant to test the wire inside the T connector. Not on the ALT...

[wayno]

It seems to me you are reading the black numbers. Read the Green numbers when checking Resistance (oHms)

 

 

But those numbers translated to oHms, is like 16oHms.

 

This is when a digital MM is nice.

 

 

Yes I was reading the black numbers, that is why I posted a photo of the meter, so even if I did it wrong, everyone that knows how to read these things would know what the actual reading was as I described where it was set, and the reading I got.

Just for grins, I just went out and connected the ign. idiot light up and started the truck, it was on when I turned the key on, and it went off when I started the engine, it smelt kinda funny when I took it over to be tested at the auto parts store earlier.

Where would I put an amp gauge to see how many amps are being forced into the battery, I don't want to smoke the battery.

That volt meter is jumping rope, it is very annoying/distracting.

[ggzilla]

I just went out and tested it on my Datsun. With key off, the Lamp (WR) wire reads 0 ohms, with my digital ohmmeter on the 100K range setting. The other wire in the T-connector was 12V with key off (Sense wire).

 

So maybe it's not a valid test.

[ggzilla]

I put an amp gauge to see how many amps are being forced into the battery, I don't want to smoke the battery.

The alternator doesn't force amps, instead the battery draws what it will. You could put a 100A alternator on and the battery would still draw the same max amps. The entire wiring system of a 1960s/1970s Datsun Truck draws maximum of 35A with headlights and heater fan on (unless something is defective, like has a partial short, or the battery is extra low). That's why datsun fitted 35A alternator to some 620s and 720s -- that's all it needs. But if battery is low it can charge faster with the optional 50A alternator.

 

Battery will smoke if it is partially shorted, if the voltage from the alternator is too high, or (most common) if the battery cables are dirty you'll see smoke from the terminals.

 

Alternator will smoke if something is wrong with it, or if overloaded (vehicle is drawing more than the alternator can supply).

 

Current = Volts/resistance (I=V/R) so if the voltage goes up, so does the current draw. The current draw (amps) can't go up by itself but only if Voltage increases or resistance (load) decreases.