JAG1

@Mopar1973Man where does the grid heater trigger wires come from? Are the relays controlled by the ECM or is it the PCM? Thanks Mike or anyone

Thanks Mike . Did you ever take that Alt. apart to find where the problem was with the blue wire in there? I am very much interested in finding what's causing lots of these Alts to get so hot you can't touch them. In Googling a search you find quite a few that have cooked their Alts, but no indication of what's causing it. I am going to invest time into looking at my starter motor cables and anything that might have rubbed to cause full sink and make a fuse stud bolt glow like that. Remember I had not started the engine, only turned the key on when the bolt glowed. luckily I had the hood open and the fuse holder up high able see it. I suspect it's still the grid heater relays somehow sticking, maybe one stuck on while the other just clicked in and so both grids running at the same time could have done that. Just looking closely at the contacts inside the old relays may be a clue as the copper looks like is splayed outward like it was melted a bit around the wear marks. It's hard to know for sure. I need to use the magnifier which might help. Also I have always had my grids disconnected thanks to Mopar1973Mans advice, except on these two mornings of which the second one was the glow bolt morning. Wonderful with coffee on a Saturday . Reason my hood was open was the burning electrical smell the day before and the earlier episode with the cooked boiled fried alt. only two mos. before. I found the 12 inch piece of wire that had the glowing bolt thru its lug and will do a voltage drop test on that and the other fuse holder installed to the other second gen truck. I also found that it was operators error on the use of the Fluke meter. I was using the wrong scale, had the decimal point in the wrong location which caused it to try reading small fractions and bouncing all over with small fractions of ohms resistance. Retesting both Alts. that were pulled shows they are not crossing B+ stud to the frame housing . Sorry for the long post as this is an education for me thanks all of you and one very drilling/ lecturing buddy down in Ca.

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

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

@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?

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.

Supposed to be getting a big arctic blast soon. I think Mopar1973Man is going to have AC ripple from shivering so much as he has no firewood. He better get some split and standing up to dry in the entry at least. Anyway I usually plug in at early morning coffee if it's below 30, but if we have an ice storm or snow all night I will plug in the night before to keep the cab warm and keep the snow/ ice melted off the windows.

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.

we used to called them 'gag burgers' I think the year was about 1966 when I Later sold my 57 chevy and bought a two year old chevy Malibu from the dealership for $1500 dollars. I think my payments where around $34 bucks a month.

@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

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.

I remember .24 a gallon and Mcdonalds right next door, hamburgers for 15 cents and all the high school gals showing up for lunch. It was fun in those days. We'd go out in the school parking lot sit in my 57 chevy for a smoke. In a few mins a gal, or anyone for that matter, would ask to sit inside for a smoke. Met lots of nice friends and made weekend plans that way many times.

Sorry you guys I did not realize the options not available to you guys. It's a weird globe we live on for sure. I liked it back in the 60's when the biggest problem was finding 3 bucks to fill my tank to go all Friday night. Those were fun nights back then. So simple.

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.

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

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.

@Mopar1973Man are you talking about a shorted cell battery running down the others, and ruining them because that shorted cell has all the other batteries in parallel while in full sink? There is a difference when talking about a controlled charge rate right? I'm asking here as I do not think the battery temp sensor is to only sense ambient temps from the weather, but actual battery temps. I do not like that the grid heater relays fail in a closed position. That is....... and I repeat....... a bad situation. There is a way to stop the codes with a manual control switch (factory relays still in use) by fooling the PCM with resistors. Don't understand that fully yet. At any rate I sure would like relays to fail in the open position via different relays for example as the grid heaters need to alternate as the PCM commands. Yes, W-T did say that would be okay also. Mike in your case it is important to save all the other expensive batteries in your solar system bank when a shorted cell causes one bad battery to go into full sink and dead short, but I think we are more concerned with saving the alternators and in some instances from burning the PCM. There is a difference......... I'm also wondering what caused your alternator to short out. Did you ever check your grid heater relays? I feel like I'm in Kindergarten swimming with some big professors here and they might turn into alligators, but this subject of saving our alternators and the PCM is important so it's okay if I get underwater a little it's worth the discussion even if I do not know everything here

If you think you made big boo boo just click the 3 dots in upper right hand corner and go down the list and click delete. Or you can click edit and remove/ change words that are not correct. I don't think you guys ever needed deleting so the only way I get to feel important is when I get to delete my own post.

Bought new grid relays tonight. $80 bucks at Oreillys'. Got home and tested/ placed ohm meter on them, not installed yet and yes voltmeter shows OL like it should. So yes my old grid heater relays are both bad, causing full tilt and smokin two alternators. lucky too that my PCM is in good shape didn't burn in either episode. It is unfortunate the grid heater relays fail in the closed position. Thats a bad deal. Im hoping someone has a solution to this problem as we have been occasionally hearing about shorted alternators. BTW everyone, if both batteries were strapped the way W-T says the temp sensor would have indeed limited the output on the alternator. As it is the temp sensor is not able to see what is happening with the passenger battery so you have to double strap for it to work. Sorry Mikey Mopie you owe me BIG milkshake for that one. Remember that with MoparMom? that was a very good time we had together. She was the best person around.

It's the work truck that cooks the alternators. I think it's from the grid heaters. Doing a search I found out about a bolt that comes loose from the isolation insulator deteriorating then shorts to ground and melting the bolt head off and the bolt drops into the intake. (no matter what you think.... no, I did not design that), but its the bolt that holds the power lead to the intake grid heaters.

Just got that! Yeah we probly won't hear from you for several days

I knew both failed alright both were smokin, now need to find out why, hence doing further testing on the relays today. When using a fluke ohm meter.... is the meter so sensitive that having 3.5 ohms resistance is what the probes crossed by themselves read? U know those grid heater relays should fail in the open position..... I think that is what is so confusing, but I guess they weld themselves shut sometimes. Don't understand the clicking yet they show they are closed when not activated

Wow! @Mopar1973Man does a short like that cause further damage to the alternator that you cannot change just the diode bridge and place it back into service?

Sometimes I feel off track and think my posts are not worth much......like when a post gets ignored because it's really not contributing much to the discussion, so I delete them occasionally. I don't delete others posts just my own when like that.

I was sure when diodes go or burn out that it doesn't mean the alternator is shorted to ground, both alternators got smokin' hot. Not sure, but I think from running full tilt for an extended amount of time trying to replenish batteries getting drained that in in full 'sink' from high load.