Tractorman

My truck is an '02 and I am the original owner. Back around 2005, warranty covered VP44 replacement and a retro-fitted in-tank lift pump. At this time the dealer relayed the lift pump using the control signal from the ECM, so I do not have to make this modification. Hats off to you for recognizing that the factory should have never wired the lift pump directly from the ECM in the first place. Great detail in showing how to make the conversion! - John

From the FSM for my '02 truck... The transfer pump is self-priming: When the key is first turned on (without cranking engine), the pump will operate for approximately 1/4 second and then shut off. The pump will also operate for up to 25 seconds after the starter is engaged, - John

The reason it works for them is because of that "Well, everybody does it!" theory. - John

The one in the in the link is 1/4" pipe thread, but still the same concept. It should be a tapered thread and it should snug up if the tapped hole hasn't been enlarged. - John

When I go to the character map, all I get is a list of the guys on the Board of Directors for this site! So it looks like you are using your phone to reply to posts. I am still using my laptop. I did go on line and found out how to do it on a windows based computer. So, with some ° of difficulty I can do it now. I have to hold the ALT key and select 0176 on the numeric keyboard. Someone with a ° must have thought this up! - John

I think that just might work. It look like the nights are going to be dropping to around 12 degrees here in about five or six days from now. I think I will park my truck outside one of those and test the theory when I start the engine the following morning. How did you get the degree symbol in the 45 degrees? - John

Almost true. When the selector is placed in the Max AC position, two separate things happen. 1. the AC compressor circuit is activated. (but the ac compressor does not necessarily turn on). 2. the vacuum controlled door that controls whether fresh air enters the cabin or whether cabin air is recirculated within the cabin shifts to cabin recirculation mode and stays there regardless of whether the ac compressor is running or not. My point in my earlier posts is that once the outside air temperature falls well below freezing for several hours (and the engine has been shut down overnight) the static refrigerant pressure will be so low that the low pressure switch likely will not allow the ac compressor to be turned on. Even if it does turn on, the cycle will be so brief that it will have very little cooling effect. So, @Dieselfuture, even if you turned on your AC compressor toggle switch under those conditions, the compressor still would not turn on and the air would still be recirculating in the cabin. I am thinking that you may already know this - I am just trying to clarify. Thanks for you patience. @Dieselfuture, I am basing all my posts on above statement in the original post. Unfortunately, the description "really cold days" can have different meanings for different people. For me a 45 degree day does not fit that description - a 25 degree day does. On a 25 degree day the compressor is not going to run, so warming up the cab in the recirc mode could work well. No arrow on mine, just a snowflake symbol. - John

You're on the Board of Directors - can't you make him wait? In my opinion the "Max AC" label is a poor choice of words to describe the function that is being performed. How about calling it "Recirc"? - since that is what it does. After all, that is what most other auto manufacturers call it. John

Not quite. Set the top selector to Max AC. This puts it into the recirculation mode. All other selections bring in outside air. I see @dripleyposted while I was writing. - John

If you are considering that an exceptionally cold is a below freezing day, then I would think that the interior of the truck could be warmed faster in the recirc mode without fogging windows as long as the interior of the cab was dry. Of course the heat would be coming out of the dash vents, but who cares if you are not in the truck. Then, like you say, you can take it out of the recirc mode when you get in the truck to drive away. I will have to try that sometime in the near future. I think you might be on to something. - John

This works fine if the outside air temperature is well above freezing. Once the outside temperature falls to freezing or below, the AC compressor cycles less and less, finally to the point it does not cycle at all if the outside temperature falls well below freezing. This is due to the low saturation pressure of the refrigerant. The recirculating heated air will warm raise the saturation pressure of the refrigerant somewhat, but the exposure of the condenser being first in line to the cold outside air will cool the refrigerant so rapidly that the saturation pressure will likely be too low to cycle the compressor. Note the saturation pressure of the refrigerant at 30 degrees in the chart below: A few years ago when my heater core was leaking, my side windows would begin fogging when it dropped to around 40 degrees outside. The fogging would creep around to the edges of the windshield and slowly worsen. With defrost selected he compressor was cycling, but the on cycles were short and the off cycle were long - not giving enough time on to dry the outside air further. With the added moisture from the coolant leak the windows would fog. I even tried setting the controls to AC recirc, but it was worse as I expected it would be. (Note, I have a refrigerant recovery system, so I had the correct weight of refrigerant in the system). At that time I needed to go on a long trip over the Cascade Mountains during the winter. I knew that I would have window fogging problems. I rigged a momentary switch that I could hold in my hand inside the cab to bypass the low pressure switch so I could run the AC compressor for as long as I chose. Once I started climbing the pass the outside temperature fell to below 40 degrees (raining and foggy) and my windows started to fog. I depressed the switch for 2 or 3 minutes followed by a release time of one minute or so and the windows cleared right up. If I were to have done this for a long period of time I am sure that the evaporator core would have started to freeze up, but it got me over the pass with great visibility. The reason I mention this trip is because it shows the limitations of the AC systems in our trucks. @Doubletrouble, your idea may work for you, but you could have window fogging under certain conditions for the reasons mentioned above. A lot will depend on the climate where you live and what the outside conditions are when you use the recirc function for heating. I know that years ago a friend of mine had a Toyota that would allow air recirculation in the cab with heat and no AC. The friend complained that sometimes the windows would fog during the cold season. He told me that he used the recirc all of the time. I suggested the he turn the recirc function off and go to defrost mode or defrost / floor mode. He did and his fogging problems disappeared (literally - ha! ha!). - John

It does seem like a good idea, but there is one thing you are overlooking. That nice warm air will never exit the cabin, consequently the air will continue to pick up moisture (from wet clothes, wet shoes, your own breath, etc.) and that moisture will begin to condense on your cold windshield and side windows. You may be warm and toasty - you just won't be able to see. By always bringing in outside air into the cabin during the heat or defrost modes, the added moisture to the air will always be exiting the cabin while fresh dry air is entering. - John

Then how do we know if it's true? We need references! - John

I don't think you can hijack a thread you started. - John

I Installed these cabin filters from Geno's after I replaced my heater core about 75,000 miles ago. I wished I would have done it when the truck was new. - John

I put an adjustable resistor in mine a few years ago. I set it at 143 degrees. I check the resister every couple of months or so to make sure it hasn't changed - so far it has remained steady. It has worked fine under all driving conditions and I don't get the heavy timing rattle on a cold engine. My morning lows have been averaging 18 degrees for the past few days. I experimented with the setting last year during the coldest part of the winter. I set it at 180 degrees - no side effects. - John

I have experimented with a couple of LED headlight bulbs, but so far they aren't outperforming my halogen Sport head light setup. I was fortunate enough to get good reflectors when I purchased the Sport headlight package a few years ago. I may not get the lumen capabilities that the LED's offer, but my halogens light the roadway as they should - both low and high beams. I use GE NIGHT HAWK XENON 9007NHX lamps as recommended by Danie Stern (Daniel Stern Lighting). - John

Oops, I overlooked the high beam indicator. I am not seeing a lot of difference in distant light output when switching to high beam. Maybe your upcoming photos will show that better. - John

@dieseldon, I couldn't tell if your photos were showing low beam and high beam separately, or were they all just low beam? Maybe you could shed some light on that (ha! ha!). Thanks, - John

Interesting what you describe - I was having the same symptoms. I never considered an injector issue since the RV275 injectors were new when this started happening on my truck. One thing I didn't mention is that the miss would go away when I used cruise control, even when it was pulling hard in 6th gear climbing a long grade. That kind of threw me a curve. I wondered if the ECM altered timing when on cruise. It was the only thing that made sense at the time. So, now I am wondering if I got a new injector with low pop pressure right out of the box. Maybe I am masking the problem by setting the timing to stock....? @Alexio Auditore, you will have to let us know what fixes your engine miss. - John

You are describing something very similar that happened to me. It did turn out to be an engine miss under the same driving conditions as you are describing. Mine started just after I installed RV275 injectors. I didn't notice it immediately because I wasn't driving anywhere to utilize the power. It showed up on my first tow (only pulling a 4,000 lb trailer), mostly when accelerating in 6th gear. It felt like when a gas engine has an irregular ignition miss and, like you say, I couldn't hear it but I could feel it under a load in the higher gears. For awhile I even thought it could be mechanical. This haunted me for about 18,000 miles. I use a Smarty S03 tuner and I even set it back to stock. The miss disappeared, but so did the engine torque. To me the test was inconclusive. I lived with it and tried various things - I even replaced the transmission mount - all to no avail. Last December I was getting tired of hearing the timing rattle (enhanced by winter blend fuel where I now live) so I set the timing back to stock and left the rest of the tune alone. Timing rattle gone and no engine miss! Under any condition! I left the timing set at stock, even through the summer. Periodically, I advance the timing just for a test and sure enough the miss returns. Running stock timing has had no adverse effect on performance or fuel economy. May not be your issue, but then again..., - John

Your first post is dated Wednesday, but I never saw this post. Your post today showed up right away. Maybe others are having the same issue. I am sure you will be getting responses soon. This is a good site for your kind of questions - it is a good source for 24 valve second generation trucks in general. My truck is an '02 with the NV5600 and a stock clutch. I have the RV275 hp injectors and a Smarty S03. I don't tow as heavy as you, but the truck runs well and has been reliable. EGT's are always below 1200 degrees. Most of my driving is between 1500 - 2200 rpm. On a rare occasion I have been up to 2500 rpm. - John

It would be interesting to see a photo of that fuse after that event occurred. What you have described is indicative of a poor electrical connection at a precise location, the fuse stud. It would also explain why the nearby fuse didn't break the circuit. Here is a possible scenario: Truck electrical system is consuming 60 amps. Poor connection at stud causes a 6 volt voltage drop at at the connection while alternator is flowing 60 amps (less than 1/2 alternator capacity) through the circuit. If a voltage drop test would be performed during the event, one might see 18 volts on the alternator side of the connection and 12 volts on the battery side of the connection. This would be a voltage drop of 6 volts while flowing 60 amps. In your case both numbers easily could have been higher. 60 amps x 6 volts = 360 watts of power at a very precise poor connection easily equals a glowing stud. Kind of like the glowing tip of a 300 watt soldering gun when not contacting any work. A very similar experience happened to my brother-in-law a few years ago. He had Les Schwab install a battery isolator and a new auxiliary battery in the engine compartment of his truck. The setup was for his slide-in truck camper. We all went camping - us in our camper, them in theirs. After several days of camping at one site, we left for to go elsewhere. At our first stop along the way, my brother-in-law says that he was sold a bad battery because it blew up just after he left the campground. We raised the hood to take a look. Sure enough part of the top and side of the battery was missing. But what wasn't missing was evidence. The battery cable eye that was still clamped with a wing nut to the positive battery post was severely discolored by heat along with burned and melted cable insulation in the immediate vicinity. Not a bad battery, but a glowing connection that ignited the hydrogen gases from a rapidly charging battery that was discharged at the previous campground. One good reason not to use wing nuts for battery connections. The point is that everything was working as it should, but a poor connection created a serious problem and a safety hazard. For all of the above reasons I do not rely on the physical appearance of electrical connections with high amperage circuits. One needs to know if the electrical continuity is good at a given connection. The only way to know that for sure is to perform a voltage drop test while the circuit is under a load. @Mopar1973Manprovides an excellent article in how to perform this test. - John

@JAG1, you are describing a camper very similar to what I used to own. Mine was a four season Citation with basement made by General Coach in Canada. The manufacturer stated that the camper weighed 2700 lbs with 20 gallons of water and two full propane tanks. With our gear thrown in, it weighed about 3,500 lbs. Combined with the truck - about 11,000 lbs - 4,850 on the front and 6,150 on the rear. As suggested by others, you should weigh the rig. Weigh each axle separately and write the weights down. You will probably find that your front axle weight will increase only about 500 lbs or less. The rest of the weight will be resting on the rear axle. I used the Rancho 9000 series shock absorber because there are 9 adjustable positions to incrementally control resistance to the hydraulic flow when the shock extends. This makes the shock perform well with a loaded or empty truck, especially a loaded truck with a high center of gravity. Let us know what the results are if you decide to weigh the rig. - John

Good suggestions and and questions that need to be answered from @AH64ID. One more question to add. Is your camper an all season camper with a basement? If so, this raises the center of gravity considerably. - John