Spyder 2.4 still won't charge after known good alternator replacement.

[SlipknotBabe99]

TLDR; replaced alternator and still not getting any voltage from it.

I will give a little preface to how this started, one night I accidentally left the dome lights on after a drive home. I came out a week later to an obviously dead battery, I jumped it and it ran fine for a few days. I let it sit in idle for a while to build the battery back up since it was always dead after turning it off. While letting it idle it started to bog and misfire and croak out due to not getting sufficient charge. I limped it into my garage and here is where it sits. As long as I have a jump pack on it, it will run and drive just fine. So far I have done the following;

Replaced the alternator with one that was tested multiple times at different stores.

Checked for continuity from alternator to alternator fuse, the fuse itself, and from fuse to battery.

Check for ground issues, made sure everything was plugged in and tightened up correctly.

Tested the original alternator and found that it also tested good.

I'm left wondering what else could be the issue. After all, the car ran perfectly fine before I left the dome lights on. Maybe there's something I'm missing. I've also been wondering if I could just try a wire directly from the alternator to the battery but not sure if that would mess anything up. Any suggestions or ideas would be greatly appreciated. I know when it comes to electrical issues, there is almost never a concrete answer.

 

[pauleyman]

Test the battery and check voltage at battery with car running. What do you get for voltage car on and off?

 

[SlipknotBabe99]

Test the battery and check voltage at battery with car running. What do you get for voltage car on and off?

While off, the battery sits at 12.2 after a good charge and will stay there until you start the car.

When it starts I'm at 11.75 and slowly drops by the second if I do not keep a jump pack on it.

 

[steve]

I assume that's measured at the battery. Try measuring at the Alternator B+ post both before and after starting the car. That will eliminate the fuse and possible cabling.

After that the next checks would be to make sure the alternator is getting power to start it's field.

You must be logged in to view this image or video.

 

[1990TSIAWDTALON]

Have you had the battery tested for a bad cell?

 

[CKOPOCT]

Depending on the age, condition, and brand of the battery, that may be your problem. Car batteries don't take being completely discharged very well (unless they are deep cycle batteries). If your battery was old you may have killed a cell or weakened it to the point it can't take a charge well enough anymore.

If everything was perfectly fine before and the only change was killing the battery by leaving the dome light on, bet it's a weak battery.

No deep corrosion on the battery terminals, right?

 

[SlipknotBabe99]

I assume that's measured at the battery. Try measuring at the Alternator B+ post both before and after starting the car. That will eliminate the fuse and possible cabling.

After that the next checks would be to make sure the alternator is getting power to start it's field.

You must be logged in to view this image or video.

I will try that when I get home from work today and see what I can find. Thank you for the schematic that should help me out a bunch.

 

[SlipknotBabe99]

Depending on the age, condition, and brand of the battery, that may be your problem. Car batteries don't take being completely discharged very well (unless they are deep cycle batteries). If your battery was old you may have killed a cell or weakened it to the point it can't take a charge well enough anymore.

If everything was perfectly fine before and the only change was killing the battery by leaving the dome light on, bet it's a weak battery.

No deep corrosion on the battery terminals, right?

So far the battery has done great, thought about trying a different battery just in case but it's not that old and I have no corrosion at all onthe terminals. All in all it seems like it's in good shape

 

[SlipknotBabe99]

I will try that when I get home from work today and see what I can find. Thank you for the schematic that should help me out a bunch.

So I went ahead and tested the alternator by putting the positive lead of my multimeter on the positive post on the alternator and the negative lead on the alternator case and only got 3.64 volts. Sounds like even though both alternators tested good at the parts store, they might both be bad.

 

[steve]

With the engine off you should see battery voltage at the B+ stud since it's connected via the alternator fuse. Once the engine starts assuming the field winding gets energized the voltage should be between battery voltage and 14.4v if the alternator is charging. The alternator gets power to start the magnetic field on pin 3 of the A-03 connector.

 

[SlipknotBabe99]

With the engine off you should see battery voltage at the B+ stud since it's connected via the alternator fuse. Once the engine starts assuming the field winding gets energized the voltage should be between battery voltage and 14.4v if the alternator is charging. The alternator gets power to start the magnetic field on pin 3 of the A-03 connector.

So car off I'm seeing 12.2 at the battery and 11.53 at the alternator. Car on slowly dropping starting at 11.73 on the battery and 3.64 solid on the alternator. Seeing 8.45 at the fuse. I apologize if I'm not understanding something correctly I'm a bit of a noob at certain electrical things. I can wire up a stereo like it's nothing but when it comes to this kind of diag I'm a little lost.

 

[SlipknotBabe99]

Further update, even with the jump pack and a charged battery, the windows will no longer go up or down, the headlights do not work, and the radio does not work anymore. I'm wondering if there's a PCM issue. The top has never worked since my ownership so that's changed.

 

[CKOPOCT]

It honestly sounds like you either have significant resistance (weak ground, bad connection, corroded wire) or an alternator that isn't putting out. Also still not convinced the battery isn't a suspect. I've seen more than a few batteries that would show 12.4+ volts sitting but would give up the ghost once a load was put to them. If you haven't done so already, I'd take the battery to your chain parts store of choice and have them test the battery - just to eliminate that possibility.

 

[SlipknotBabe99]

I am going to try a new alternator, a new battery, and possibly a new pcm. Does anyone know if pcms are plug n play on the 4g64? I have been trying to find some info but haven't had any luck. I am trying to figure it out before I go ahead and pick one up.

 

[99dsmer4g63]

If you are not seeing battery voltage on the alternator post with the car off I’d suspect the wiring to be the culprit possibly.

Does the battery light illuminate on the dash when you turn the key to the on position? Also if yes does the battery and brake light stay on after starting the car or do both turn off after starting and releasing e brake?

-Daniel

 

[chrysler kid]

Its the alternator

They need to be tested on vehicle

If the engine is running and you see battery voltage at the battery while the engine is running of less than 13volts the alternator is not working

Now that we know the alternator is not working you need to inspect the plug for the alternator for damage, and the fuse for the alternator in the underhood fuse box.

If the plug looks good and the alternator fuse has connectivity then the alternator is bad.

I work at an autoparts store and can tell you the ones being sold are typically 10+ years old on the shelf and 3 out of 5 will not work when installed, but still bench test good

 

[SlipknotBabe99]

If you are not seeing battery voltage on the alternator post with the car off I’d suspect the wiring to be the culprit possibly.

Does the battery light illuminate on the dash when you turn the key to the on position? Also if yes does the battery and brake light stay on after starting the car or do both turn off after starting and releasing e brake?

-Daniel

I do see battery voltage at the alternator with the car off. Battery light is on with key and Battery and e brake light stay on with the car on, emergency brake is not pulled.

 

[SlipknotBabe99]

Its the alternator

They need to be tested on vehicle

If the engine is running and you see battery voltage at the battery while the engine is running of less than 13volts the alternator is not working

Now that we know the alternator is not working you need to inspect the plug for the alternator for damage, and the fuse for the alternator in the underhood fuse box.

If the plug looks good and the alternator fuse has connectivity then the alternator is bad.

I work at an autoparts store and can tell you the ones being sold are typically 10+ years old on the shelf and 3 out of 5 will not work when installed, but still bench test good

As someone who also works at a parts store, I definitely agree there are parts that have been sitting a long time. I also believe the remanufacturer process uses the cheapest parts they can find. I understand your rationale for the alternator not working. But I'm not entirely convinced that the trigger wire is working. As Steve said earlier in the thread, "The alternator gets power to start the magnetic field on pin 3 of the A-03 connector." I have to figure out how to verify it's getting told to start up. I'm going to try to source another alternator regardless. I tried going the cheap route by grabbing a used OEM one but I can't even verify the parts store tester even works good.

 

[1990TSIAWDTALON]

Jumper 12v from the battery lug to pin 3 momentarily to see if the alternator will start charging. That will tell you if pin 3 is ever seeing voltage to start the field.

 

[steve]

If you're seeing the battery light on the gauge cluster it means 12v is reaching it and something on the other side is grounding. Normally that would be the alternator but as you can see from the diagram there are other connections to the same, like the one off to the ABS on a FWD.

Checking the black/yellow wire to pin 3 to see if there is 12v with key on engine off and that it doesn't have continuity to ground when the key is off would help diagnose.

 

[99dsmer4g63]

I do see battery voltage at the alternator with the car off. Battery light is on with key and Battery and e brake light stay on with the car on, emergency brake is not pulled.

Okay please do what Steve said then and post back with the results. I’ve had my rounds with my charging system in the past and have already been down the road of throwing alternators at it. Turns out it wasn’t the alternator. If the alternator isn’t being told what to do its not going to charge.

-Daniel

 

[SlipknotBabe99]

Okay please do what Steve said then and post back with the results. I’ve had my rounds with my charging system in the past and have already been down the road of throwing alternators at it. Turns out it wasn’t the alternator. If the alternator isn’t being told what to do its not going to charge.

-Daniel

I will try this when I get home from work tonight. Thanks a bunch!

 

[SlipknotBabe99]

So I installed a brand new battery and redid both my terminals and a new ground wire.

Some things to note that I have seen.

The headlights will turn on and stay on without the switch being touched
The radio no longer works
The windows no longer work
The door lights no longer work

These are all things that have been a problem since the beginning. I'm preparing to probe pin 3 on the alternator, trying to verify which one is which and trying to find something to probe with.

 

[SlipknotBabe99]

Both black/yellow and pin 3 do not have continuity to ground.

When checking for voltage;
0.93v key on engine off.
Key off 12.24v.

 

[SlipknotBabe99]

Both black/yellow and pin 3 do not have continuity to ground.

When checking for voltage;
0.93v key on engine off.
Key off 12.24v.

Also, weird thing when testing the alternator fuse again my horn went off for a split second and my interior lights worked. This is just with one probe, the other on nothing