Battery Temp Sensor question

[JAG1]

3 minutes ago, LorenS said:

But even if all cables are the same today, they won't be after awhile.  That's kind of the whole point of this.  I'd prefer my driver's batter be undercharged than my passenger side battery getting the life boiled out of it because the alternator is pumping the juice to it trying to overcome an (inevitable) bad connection.    We don't all live in the dry climate of Idaho where battery connections last millennia.

I do religiously check my cables based on your teachings so am not too worried about it, but for others, moving the sensor may make the most sense.

Yes, we need a way to save the alternators, some very expensive and in some cases the PCM which it's getting harder to find reputable repair companies.

1 hour ago, Mopar1973Man said:

 

Can't for smog controlled states being it will set the CEL and P0380 and P0382... This is why I unhook my grid heaters in April and leave unhooked till October. The power lead is right at the drivers side battery positive. Takes less than 5 seconds to deal with.

 

Most morning I don't even WAIT TO START I just hit the key and go. This winter has been super mild and not really gotten below 32*F for long. 

After the trucks starts and idles nice do you unhook the grid heaters at that point? I ask because leaving them hooked up when one fails is a bad deal.

[Dieselfuture]

1 hour ago, Mopar1973Man said:

Can't for smog controlled states being it will set the CEL and P0380 and P0382...

Just hook it back to normal before doing the test if required, may need a cheap scan tool to clear codes. It sets 2 codes like you said but no light on the dash. 

[Royal Squire]

57 minutes ago, JAG1 said:

Yes, we need a way to save the alternators, some very expensive and in some cases the PCM which it's getting harder to find reputable repair companies.

After the trucks starts and idles nice do you unhook the grid heaters at that point? I ask because leaving them hooked up when one fails is a bad deal.

You can install @IBMobilegrid heater mod as I have. Works very well. 

[JAG1]

1 hour ago, Royal Squire said:

You can install @IBMobilegrid heater mod as I have. Works very well. 

I had it in there but not knowing what burned two alternators within a few months I disconnected it and took it out.

[Dieselfuture]

19 minutes ago, JAG1 said:

I had it in there but not knowing what burned two alternators within a few months I disconnected it and took it out.

[JAG1]

9 hours ago, Dieselfuture said:

I can put it back in real easy, the bracket still in there, but but but I sound like a model A......... W-T is coming out with a new system of switching.

 

Pictures coming tomorrow showing the burn contact on the grid heater relays. They are made pretty well after taking the two old ones apart. The only way they can fail closed is when they get fused together otherwise it is very rare that it happens.

 

 

[Dieselfuture]

1 minute ago, JAG1 said:

I can put it back in real easy, the bracket still in there, but but but I sound like a model A......... W-T is coming out with a new system of switching.

 

Pictures coming tomorrow showing the burn contact on the grid heater relays. They are made pretty well after taking the two old ones apart. The only way they can fail closed is when they get fused together otherwise it is very rare that it happens.

 

 

[JAG1]

 

Her you go @Diselfuture and others........

Promised pics of my new AFF creeper. I pressed two sockets near the headrest into the factory holes to hold two magnetic lights'

 

Anyway you can see the contacts are burned. The silver round cylinder is the coil that pushes vertically upward to the two contacts above. It's a good design IMO. Im sorry about telling everyone they fail in the closed position, as you can see the spring on top of the round 'cookie shaped' moving contact that goes up and down with a spring to push away just incase they are sticking. My OHM meter is acting up by showing different readings while activating the relays on a test, which lead me to believe they were closed. That's not to say that sometimes they didn't stick as the truck has 240k on it. I think sometimes they did stick together as you can see the damaged contacts in the photo.

 

Jee Wiz I had a hard time getting up these photos. Got frustrated so Bad had to go out and work on my other truck for therapy. Why can't computers just say what it is instead of all these names they make up? Like bolts washers nuts wrenches and beer..... I hope they don't screw those up.

Edited February 6, 2021 by JAG1

[Tractorman]

1 hour ago, JAG1 said:

Anyway you can see the contacts are burned. The silver round cylinder is the coil that pushes vertically upward to the two contacts above. It's a good design IMO. Im sorry about telling everyone they fail in the closed position, as you can see the spring on top of the round 'cookie shaped' moving contact that goes up and down with a spring to push away just incase they are sticking.

 

Thank you for acknowledging and posting the fact that solenoids didn't fail in the closed position.  I was having trouble understanding how  a solenoid failing in the closed position would not discharge your batteries rapidly while the truck was shut off and to not see a low dash voltage gauge reading while the truck was running.  

 

So, is it correct to assume at this time that you have had two alternator failures with unknown causes?

 

- John

[JAG1]

@TractormanI'm not sure at this time John I suppose it is possible, that one of the relays or maybe both at one time or another did stay closed. It is the only thing that has enough draw to make the alternator go into full sink to be shorted and overheating.  My volt meter shows they both where closed when tested using ohms. Later test on the bench showed open as they should, but would give different results when clicking on and off. It gets to the point that you just want to put in the new and forget about it.

 

While testing the new relays on the bench they too showed 15 ohms while open unless my meter is wrong, I think it is reading something from the coil plunger as there is no protection diode in there like the relay we all use for the electric lift pumps. My experience is limited

[JAG1]

13 hours ago, Tractorman said:

 

Thank you for acknowledging and posting the fact that solenoids didn't fail in the closed position.  I was having trouble understanding how  a solenoid failing in the closed position would not discharge your batteries rapidly while the truck was shut off and to not see a low dash voltage gauge reading while the truck was running.  

 

So, is it correct to assume at this time that you have had two alternator failures with unknown causes?

 

- John

You brought up a very good point here John.... I just wonder what else could cause the huge battery draw that would cause the PCM to signal the alternator to go to full output.. The grid heaters are the only thing I can think of besides the starter motor, but then you would be able to hear it running if it did not shut down after start up. So at this point I can only assume that one or both relays were faulty and sticking closed at times. Anyone care to mention anything else I should be looking for? The truck has been fine for a couple months since not using the grid heaters and now the relays are replaced I'm hoping the problem is solved. 

 

It was very weird seeing the lug bolt to the fuse holder (battery side terminal bolt) glowing instantly like a light bulb, Fuse was mounted up high and I was lucky enough to have the hood open, see it and shut off the key and yet did not blow the fuse. The fuse is silver coated and the silvering was melted off only on the battery side of the fuse. Very weird.

 

Should I be looking elsewhere for a problem? I think yes, can't hurt and I'm going to look at the grid heater studs on the intake to make sure the isolators or insulators aren't grounding there. Maybe we can slow down the number of hot alternators we keep hearing about.

Edited February 7, 2021 by JAG1

[IBMobile]

1 hour ago, JAG1 said:

I'm going to look at the grid heater studs on the intake to make sure the isolators or insulators aren't grounding there.

You would think if a grid heater insulator was bad and shorting to ground then the fusible link in the cable between the battery and the relay for that grid heater would open circuit  

[JAG1]

9 minutes ago, IBMobile said:

You would think if a grid heater insulator was bad and shorting to ground then the fusible link in the cable between the battery and the relay for that grid heater would open circuit  

Your right about that Dan. It's just sometimes when the word 'electrical' enters this space it echoes in there ya know!

 

I have one thing important to say ..... there are enough problems with smokin hot alternators on our Dodges that it brings me to a very important question........ why can't the voltage regulator inside the PCM do it's job and regulate the voltage properly by saving diodes, instead of letting it go to full tilt and shorting out. It's a dang fire hazard from what I have experienced. I am very much disliking the factory VR. I think it's a real problem and most know it is better to charge a slower rate of charge for batteries than an alternator killing level. Now I ask....... the little 5 amp fuse placed on the alternator control wires to save the PCM from burning...... my reading tells me sensitive electronics will often blow before a fuse..... is this situation like the lift pumps where isolating them from the ECM to protect it is a good idea.? My thoughts are to have a regulator that does just that....... isolated from the PCM and actually regulates and limits the demands on the alternator.

 

What you have to say or any thoughts I will appreciate. 

[Mopar1973Man]

2 hours ago, JAG1 said:

I just wonder what else could cause the huge battery draw that would cause the PCM to signal the alternator to go to full output..

 

A short on the green wire of the field to grounds will do exactly that.

A grid heater(s) commanded for excessive long time or contacts arced and held excessive.

 

Like with my landlord truck (Russ) his blew the alternator and the charging fuse by using his winch with weak batteries placing nearly 100% of the load on the alternator.

 

Alternator is never suppose to hold the entire load of the vehicle it suppose to hold the loads on the batteries and alternator fills in a balance charge to maintain 13.5 to 14.5 this rule will not change. Now if the batteries do not have the capacity for said electrical load it will force the alternator to make up what the batteries will not hold. Again this comes back to weak batteries and excessive loads.

 

Starting out with my old school halogen lights (45w /65w) and 4 flood lights (100w a bulb)

 

This is one reason why I ditch the four 100w flood light I had below my bumper (400 watts / 14.5 volts = 27.5 Amps DC) then the old stock headlights are 45w lo and 65w hi beam (90w / 14.5 volts = 6.2 Amp DC) this is a total that is a total of front lights excluding markers and tails is already 39.9 Amps DC for my old setup. 

 

Upgraded to HID's and LED driving light. 

 

Now I've got Morimoto HID's which are 35w a side so that is 70w total. (70 watts / 14.5 volts = 4.8 Amps DC) then changed out the four 100w halogen bulbs for 2 PIAA 530 LED Driving lights which is 18 watts each which is 36 watts for the pair. (36 watts / 14.5 volts = 2.4 Amps DC).

 

Before - Total watts and Amps - 578.5 watts at 14.5 volts DC, drawing 39.9 Amps DC

After - Total watts and Amps - 104.4 watts at 14.5 volts DC, drawing 7.2 Amps DC - Extra gain with huge bonus of better light over any halogen bulb. (rated for 4,000 lumens). This is a total of 554% saving compare to the old school system I had. 

 

Total savings or power which is 474 watts and 32.7 Amps not used by the alternator in just lighting upgrades. 

 

Remember we have a stock alternator rated for 136 Amps. 

 

I'm not looking for bigger alternator just better efficient lighting and other electrical items. Just looking at my tail lights most of them are 250mA a bulb again a big saving of power vs. old incandescent bulbs the truck was made with. Just now looking at all my changes I've free up a bunch of the alternator and much less to power.  I've even though about pulling the tail light fuse and replacing the 15A with a 2.5 amp which is still over kill. Again seeing the electric saving in being able to swap out a fuse to such a small size. 

 

LED and HID light is a best option for reducing electrical load. 

Edited February 7, 2021 by Mopar1973Man

[JAG1]

 @Mopar1973ManA good voltage regulator could protect the alternator and the PCM. Did you ever learn what shorted out your alternator Mike? Was it those 4 lights?

[Tractorman]

3 hours ago, JAG1 said:

It was very weird seeing the lug bolt to the fuse holder (battery side terminal bolt) glowing instantly like a light bulb, Fuse was mounted up high and I was lucky enough to have the hood open, see it and shut off the key and yet did not blow the fuse. The fuse is silver coated and the silvering was melted off only on the battery side of the fuse. Very weird.

 

@JAG1, this is very good detailed information which may help diagnose your failing alternators.  I need to confirm -  are you talking about the fuse you installed in the charge wire to the passenger side battery.  I am assuming that you are.

 

3 hours ago, JAG1 said:

It was very weird seeing the lug bolt to the fuse holder (battery side terminal bolt) glowing instantly like a light bulb

 

3 hours ago, JAG1 said:

The fuse is silver coated and the silvering was melted off only on the battery side of the fuse. Very weird.

 

There is no mystery about the glowing bolt.  The glowing bolt scene is telling you something very specific and emphasizes the importance of a good electrical connection.  Just because a  connector is tight does not mean the connector has a good electrical connection.  This is also why I do not rely on physical inspections when it comes to wiring connections that handle high current loads - I perform  voltage drop tests, but more about that later.  They are easy to do and give you very accurate information about the condition of a connection.

 

The only thing that can make that bolt glow is a poor connection at that exact location.  The proof is that the fuse did not blow (because the current did not exceed its rating) and the other connector on the alternator side of the fuse holder was electrically sound. So, regardless of which way the current was flowing (charging current flowing to battery or battery current flowing to failed shorted alternator), the poor connection is a problem of its own and needs to be fixed.

 

I still don't know what caused your alternator failures, but detailed observations like the one from you above should get us there.  Can you describe the failed part or parts on each alternator?

 

- John

 

- John

 

[IBMobile]

2 hours ago, JAG1 said:

Now I ask....... the little 5 amp fuse placed on the alternator control wires to save the PCM from burning...... my reading tells me sensitive electronics will often blow before a fuse.....

These are the readings when I measured the current on the blue wire with the following on: engine, headlights, radio, fan motor high speed, and NO grid heaters.  I added a 7.5 amp fuse in the blue wire where @Mopar1973Manopted for a 5 amp fuse.  Some members that have done this modification reported that the installed 5 amp fuse would blow but the 7.5 would hold.    

 

   12.06 vdc   4.53 amp

[JAG1]

John @Tractorman , the glowing bolt on the batt side of the aftermarket fuse was on the charge wire. The key was on when it glowed, but engine was not started. I took out that section of wire about 12'' long from positive post to fuse stud holder and tested it with an ohm meter. I had zero ohms resistance. 

 

I understand the shorted alternator that happened the day before caused full sink and the bolt glowing the next morning. I will also do a voltage drop test on it and report back.

 

Also I have not taken apart the Alt yet, only found that they short to ground or the frame.

 

I will keep working on this till we find it. I do understand other things may have contributed to this situation.

 

I thank everyone that helps shed light on this.... no pun intended lol.

 

I think we are also going to find that we need  protection diodes on the correct trigger wires to the grid heater relays. Just like the lift pump relay protecting the ECM

Edited February 7, 2021 by JAG1

[Tractorman]

36 minutes ago, JAG1 said:

John @Tractorman , the glowing bolt on the batt side of the aftermarket fuse was on the charge wire. The key was on when it glowed, but engine was not started.

 

This is more very good information for diagnostics.  This confirms that a large amount of current was flowing from the battery to the alternator.  The glowing bolt confirms that the specific connection was a very poor connection - one with high resistance.  The fuse did not blow because even though the current flow was high, it was still below the fuse rating.  The rest of the wiring and connections were likely good because they did not get hot and handled the amperage load properly.

 

48 minutes ago, JAG1 said:

I took out that section of wire about 12'' long from positive post to fuse stud holder and tested it with an ohm meter. I had zero ohms resistance.

 

This test has absolutely zero value for high current applications.  Perform a simple test.  Separate a single strand of wire from a 16 gauge mulit-strand wire.  Cut the single strand wire to 12 inches in length.  Test it with your ohmmeter - you will find that it reads zero ohms of resistance.  Would you use that single strand wire for your charge wire?

 

Keep the information coming.  I would like to find out what exactly happened to your alternators.

 

- John

 

[JAG1]

Thank you John, what a fine example of an answere on ohms versus voltage drop test. 

 

Further development is that I got out my less expensive RCC voltmeter and proved the Fuke has a problem with the ohm setting, but the biggest find is that the Alts' are not crossing over the frame of the unit to the charge stud on the back of either the Bosch nor the N Denso.  ND is the one that got extremely hot. I am going to look at positive cables wear / rub spots to ground. I do want everyone to know after the truck sat for almost a week the the Batts were resting at 12.6. That's a good sign, but why the hot glowing bolt? I intend on finding out for the sake of many that are experiencing hot ALT's