Tractorman

Even if the output wire of the alternator is routed to the battery with the battery temperature sensor and that battery has a shorted cell, the battery temperature sensor will not stop the alternator from doing what it is commanded. From the example I gave previously: the shorted cell demands 50 amps (this time the driver side battery), the rest of the electrical system demands 25 amps (75 amps total). Let's say the battery temperature sensor tells the PCM to target for 13.8 volts. At the moment the alternator will be commanded by the electronic voltage regulator inside the PCM to reach the target voltage of 13.8 volts. To maintain that voltage, the alternator must keep delivering 75 amps. The battery temperature begins to rise (because of the shorted cell) so the battery temperature sensor sends this information to the PCM. The PCM decides to reduce target voltage to 13.5 volts, but nothing else has changed - the shorted cell still draws 50 amps and the remaining electrical load of 25 amps is still there, so the alternator continues to deliver 75 amps - 50 amps of unnecessary power to the shorted cell . This cycle will likely continue until the battery temperature sensor reaches its lower limits (which would have to be above battery static voltage), or the battery reaches a point that it can dissipate heat as rapidly as it is generating heat. But, meanwhile, the alternator will continue to do what it is commanded to do, and that is to deliver whatever amperage is needed to fulfill the target voltage. If the battery temperature sensor had the ability to limit target voltage to below normal battery static voltage, then many electronic components would be compromised - much more costly than an alternator. @Mopar1973Man, gives good examples of the benefits of performing equalizing charges on batteries to extend their life with his solar charging system for his house. But equalizing charges may not be as effective with some of our truck batteries. Not all batteries are equal when it comes to the quality of construction of the battery. Many times the failure of older batteries is simply the infrastructure supporting the cells fails and creates open or shorted circuits. Our trucks do not give batteries the smoothest ride. Good batteries and good electrical connections are key to long lasting alternators and electronic components. - John

I think that there is some misunderstanding regarding the purpose of the battery temperature sensor. The following is my understanding of how the charging system works: The battery temperature sensor is there to determine the target upper limit voltage of the charging system based on the temperature of the battery. By regulating the upper limit voltage (target voltage) at different values for different ambient temperatures, it gives a longer life span for the batteries. The battery temperature sensor does not control alternator output voltage at any time when the electrical load drops below the target voltage. Example: It's a hot day. The battery temperature sensor dictates target voltage to be 13.8 volts. @JAG1has wired his alternator output wire to the driver side battery because WT said so.... just kidding here. The passenger side battery has a shorted cell that is drawing 50 amps. The rest of the electrical load is 25 amps - a total of 75 amps. Charging voltage will fall below the targeted 13.8 volts and the internal voltage regulator in the PCM will tell the alternator to pick up the pace and put out whatever amperage is necessary to reach the target voltage of 13.8 volts. In this case the alternator will need to charge continuously at the 75 amp rate. So, moving the alternator output wire to the driver side battery does not help in this scenario. As @Mopar1973Man has said many times...., the batteries and electrical connections have to be in good operating condition so the charging system can operate properly. Demanding that the battery temperature sensor should be able to protect the alternator is akin to saying that the engine thermostat should be able to protect the engine when the radiator is plugged. or the water pump has stopped turning. - John

I think your return fuel back pressure concern is valid, but it may not be a problem at all. The real problem is that there is no place I know of to get the information as what is the maximum fuel return pressure allowed. I would give Blue Chip Diesel a call - they may have some information for you. Or, call a VP44 fuel injection pump rebuilder. - John

The OEM flasher requires a specific electrical to pass through the unit. The purpose is to let the driver know if a bulb is out (electrical load is reduced and flasher will flash rapidly) The heavy duty flasher requires a minimum electrical load. Even if one LED bulb is installed in the turn signal circuit, the reduced electrical load will cause the flasher to flash rapidly. The LED emergency hazard / turn signal flasher works properly with all incandescent bulb, all LED's, or a mix of both. I purchased the unit below at Autozone. The LED flasher sound level is slightly quieter than OEM and the cadence is slightly faster than OEM. I slowly switched over to all LED"s and the unit has performed flawlessly for over a year now. - John

Sanding the contacts may seem like a good idea, but there is a special coating of only a few 10,0000 of an inch thick on each contact that allows for the electrical cleaning of the contacts when the flasher operates. Sanding will remove that coating (which is probably gone already), so the fix will only be temporary. - John

I didn't know that, but it's a great idea! Would it be possible to post that information as a one liner at the top of the page for a few days so everyone would be able to see it? Something like, "Help Hint - Hover over any acronym with a dotted underline and view the meaning." - John

It is "center axle disconnect". I should have written the works and not assumed that everyone would know what CAD means. - John

You are experiencing an unusual symptom. I am assuming that you have a manual selector for the transfer case. To simplify troubleshooting, I would disconnect both vacuum lines from the CAD. Select 2 HIGH with the transfer case lever. Turn the engine off, set the park brake, and place the transmission in Park or 1st gear (if a manual). Go under the truck and ensure the front drive shaft rotates freely. This confirms that the CAD is disconnected. Select 4 HIGH and check front driveshaft rotation - it should be locked up. If it is not locked up, then you have a transfer case shifter issue or a problem inside the transfer case. If the front driveshaft is locked up, then you have a CAD mechanical problem or poor vacuum supply to the CAD vacuum motor. To check out the CAD operation I would use a vacuum pump and whatever suitable hose I had laying around to make up a temporary vacuum line that I could bring into the cab. I would hook one end of the line directly to the correct port on the CAD motor and leave the other port open for venting. I would connect the other end of the line inside the cab to the vacuum pump and operate the pump to at least 20" of vacuum. Verify the vacuum is holding and test 4 LOW and 4 HIGH operation. If the CAD works properly, then you have a vacuum supply problem. If the CAD doesn't work properly, then you have CAD mechanical problem. - John

@dave110, you are correct. I added my own momentary grid heater switch in the cab when my truck was new so I could be the boss of the grid heaters. Just the other morning it was 11° outside. I operated the grid heaters for about 15 to 20 seconds and started the engine - no post cycling to tax the alternator, so the batteries quickly recharged. No need to use the grid heaters for the rest of the day. A very inexpensive modification with great results - a win win situation. I am sure that the mod has added life to the alternator. - John

@Mopar1973Man, I think you must have had an off day. Even without the fuse modification in the circuit, I know you would have normally checked the field supply voltage to the alternator before condemning the alternator. I hope the Bosch alternator works out for you. I am still running the original Bosch alternator in my truck. - John

That is a great story! Some of the most embarrassing things we do are the best teachers! Once onboard my ship when I was in the Navy (back when I knew everything) I was assigned the task of filling a grease gun from a container of grease. Well, that should be simple enough. I removed the head of the grease gun, pulled out the plunger against its internal spring and hooked the T-handle under the edge of a workbench table top. I kept tension by holding the barrel upward with one hand while putting grease into the top of the barrel with the other hand. All was going well until the T-handle slipped and the top of the barrel came up and hit my chin. That hurt, but the event wasn't over. With the open end of the grease gun firmly imbedded into my chin, the grease discharged up past my mouth into my nose and filled the cavity between my glasses and my right eye. I froze while contemplating my situation, but I was even more focused on another thought..., did anyone see this happen? Fortunately for me, no one did. It took a long time to clean up the mess. I still had one problem; I was right back where I started - I needed to fill the grease gun. So, this time I studied the grease a bit and I noticed the lock tab to hold the plunger in place when it was pulled out. Things went better after that. When I returned to the group with a full grease gun, I was asked why it took so long. My answer was not truthful. - John

I knew someone might mention that because I thought of it myself, but I just couldn't resist. I apologize to any offended throttle bodies. - John

Yikes! Moving parts between the turbo and the engine? - John

How does that work if someone is stealing your truck? Do you tap on the window and ask the thief to reach in the back and hand you your high idle stick? I guess some thieves are more friendly than others, so it might work. I think a better anti-theft approach would an innovative security product using the "dead pedal" feature which is already standard on our trucks. - John

So, are you saying the redhead is a cheerleader? You may want to keep that quiet if your significant other is around. - John

Not necessarily. I think that the predominant surrounding environment, the duty cycle of the truck, and the quality of the battery play a large role as well. I bought a 1991 Ford F150 4x4 truck new and immediately installed a Cummins 4BTA 3.9 liter engine. The OEM external voltage regulator was located in the right side fender well. After five years of driving in the vicinity of Leadville, Colorado (10,200 ft elevation) and four years of driving in Redding, California (100° everyday throughout the summer), the single battery was still passing load tests after 9 years and over 200,000 miles of operation. I like the idea of a temperature sensor under the battery to increase battery life, but if the PCM on my truck fails to charge the batteries properly, I will more than likely switch to an external voltage regulator. . On my current truck the OEM batteries lasted for 10 years (178,000 miles). The second set lasted 6 years (115,000 miles). The current set (Group 24's) have been in use for 3 1/2 years (about 45,000 miles). I think my OEM batteries were the best quality. - John

Since you are the origin of this post, I am giving you all the credit for making me think outside the box. I did a test the other morning - a 15° morning. I started the truck and put the selector to Max AC (recirc) and set the fan to a high setting. The cab definitely warmed faster, but was slow to melt frost on the windshield. I can already see another improvement on the horizon - to be able to use any mode (such as defrost) while recirc is selected. It would seem that this combination would clear the windshield quickly while warming the cab faster. I am going get a vacuum control switch to operate the recirc door independently and make the modification soon. This morning ( a 25° morning) I warmed up my wife's ice covered TDI Passat. I selected recirc and defrost (because you can!) and both the windshield cleared and the cab warmed quickly. So thanks again @Doubletrouble! - John

That sounds like a good solution. I probably would have gone to a mechanical pump for reliability, but since my original VP44 and lift pump were replaced under warranty way back in 2005, I stayed with the in-tank lift pump and fuel pump relay provided by the Dodge dealer. I have since removed the in-tank lift pump and mounted a used frame-rail FASS DRP-2 lift pump with a coarse screen on the suction side. I still use the stock fuel filtration downstream of the lift pump. I did this mod in the Spring of 2016, almost 100,000 miles ago. I carry another used FASS lift pump with me for an emergency roadside replacement if necessary. - John

What really makes no sense to me is why did Cummins drop the OEM mechanical pump when the 24 valve engine came out? Not only was it a very reliable lift pump, but there was also a hand operated plunger as part of that pump to use for priming when necessary. It would seem that the pump could have easily been modified by Cummins for the flow requirements of the VP44. Then the wheel would not have had to bee re-invented and all of the lift pump issues for the 24 valve engines would have never happened. - John

After traveling freeway speeds for a awhile I would just stop at a rest area and put my hand on the carrier bearing to feel for temperature. Normal condition would be for the bearing to run just warmer than ambient temperature. This bearing does not receive much of a load - just keeps the driveshaft centered. When I had around 290,000 miles on the original bearing, I started noticing that the bearing began to run warmer than usual. I changed it out then. Also, this is a good time for you to take apart the slip yoke and thoroughly clean out the old grease and put in new grease. A sticking slip yoke can cause launch shudder and vibrations. Many times launch shudder is misdiagnosed and the real culprit is a sticking slip yoke. This has happened twice with my truck over approximately 347,000 miles. - John

What you are reporting is what I would expect. Good to know that it warms your cab faster. I had the perfect opportunity to experiment with the recirc setting the other morning as it was down to 15°. But..., I forgot to park the truck outside. I should get another opportunity soon. Thanks for reporting back. - John

Intermission Please take 10 minutes and refresh your popcorn! - John

@Dieselfuture asked you if that fogs your windows up more. You said, Ok, in mind I see a conflict here. How are you getting cold air from outside if it is in "full time recirculate"? - John

I commend you for being so considerate to your neighbors. Using the block heater is a great solution. You are a good neighbor! - John

I don't think moving the lift pump to the frame should make a difference, either. In fact, I installed a used frame-mounted FASS lift pump a few years ago. It is run by the fuel pump relay that a Dealer installed in 2005 along with my VP44 replacement and in-tank lift pump conversion that was done under warranty at that time. I use a fuel pressure switch with an LED indicator lamp in the dash for my low fuel pressure warning system. Even with only a 1/4 second bump my fuel pressure warning lamp goes out briefly when I turn the ignition switch to "run". I know I am not much help here, I just wanted you to have something similar to compare to. - John