crusty

The electromechanical fan clutch has been around for close to 20 years. The first one I remember was on a Cummins Ram truck. Thought it was pretty trick back then. From what I can tell there are no codes because none of the electrical circuits are broken. The clutch just doesn't hook up when told to do so. Happens to thermal fan clutches as well. This just has electrical control instead of a thermal spring. Kinda strange to call it a clutch since there is no friction material inside. Just the flow of silicone fluid that controls the coupling. Something gave up on the control. Not common, but not unheard of either.

A dealer Consult service tool will show all the details. It can also do an active test and force it to run. The trigger for the electric fan is based on vehicle speed, engine temp, A/C pressure. Now being you have a 2018 with the 5.6 you have a second electrically controlled fan. That is the engine driven fan. As I recall, that one doesn't really have any decent scan tool options. The fan clutch can fail and the fan won't move any meaningful airflow. The initial description of what you are looking for sounds like you are searching for info on the electric fan. What it sounds like is the fan clutch isn't working. So not sure which fan issue you have, or if both?

There is a fill and spill port on the pan. Add fluid until it spills from that stand pipe. Common on most new cars and trucks. Overfilling transmissions, or putting the wrong fluid in them is really bad. If it isn't leaking out, it is still full. Modern engines and transmissions are really good at not leaking.

Not every flat tire is 0PSI. You can have a leak and be low, but not zero. Keep waiting, it will eventually get to zero. The relay exists, but is part of the computer. Not user servicable or even accessable. Keep people from doing the wrong thing.

35PSI on the low side without the compressor running isn't enough. That low of a pressure is where the compressor kicks off. You have a leak. Look along the lines and fittings for a oily/dirty spot. That is where your leak is at. You are not going to fix it chasing electrical, that isn't your issue.

If you have the proper trailer wiring kit, there isn't anything going up to the battery. The harness has everything in it. Here are the instructions direct from Nissan https://www.nissan-techinfo.com/asistgc_1/USENG/diskdocs/1/T/H/1TH29.PDF Sounds like you have a tail light convertor box. They are trouble prone. I've had to use them in the past. They tend to fail in short order. Nissan's don't like them, they have been known to damage the BCM (expensive computer that runs the body and you can't live without it). The factory tow harness has all the circuits isolated correctly by engineers who designed the original wiring system.

Full coverage insurance? This is a fire claim. Did that to a Dodge many years ago.

When you say newly cut key, do you mean a copy of a key? Or did you get the key code and have one cut from the code? Don't know of any cronic lock issues. If the prior owner used it 20 times a day, every day, it could just be worn out. And no telling what someone may have done and what was the reason behind what they choose to do what they did.

The two holes with the wire mesh, they are not stock. Not sure where they go. The paint brush skirting at the bottom isn't stock either, never seen that one before.

Smelling Freon? Are you sure you are not smelling antifreeze? If you are smelling freon you have a big leak and it will be empty in minutes.

If it is just the expansion valve at the evaporator, that can be done from under the hood. If it really is the evaporator core itself, take out the seats glovebox, and center console. Unhook the electrical on both pillars, A-pillar trim. steering shaft. Couple bolts on each side of the dash beam to the pillars. Probably a few more hidden bolts. Take the whole dash out in one piece. Just like how it was built, but backwards. Trying to take the dash apart layer by layer ends up being harder, you take more apart, and way harder to put it back together correctly. The original engineering was for it to be built in one piece, just follow that.

Backordered = will be available Discontinued = now you are in trouble. Expectations that every part needed will always be in stock = unrealistic. A few years ago I had a new Ram truck that needed a new wheel. Brand new truck, there were wheels exactly what I needed on the new car lot. But it took almost a year to get that correct matching factory wheel on a vehicle that was in production.

Also look at Titan XD. The front frame section is nearly identical. Must be XD, not a regular Titan.

The dual post mirrors are extendable, all years. The single post mirrors are not.

Correct, mostly. The early V8 did have the 3.54 ratio. Once the V8 got the 7-speed they all got the 3.36. Go aback in history when the Titan was launched with this 5-speed transmission. Nissan claimed the 3.36 ratio was like others 4.10 ratio. The logic/math was the 5-speed had a much lower 1st gear. So the standing start was very close. But the Nissan 5-speed overdrive ratio was also very different as well. The normal 4-speed transmissions that were out at the time had 0.70-0.75 overdrive. While the Nissan had only .85 overdrive. If you wanted to play even more, the Titan XD diesel has a 3.92 ratio in the same axle design that can be swapped into the Van's axle. Or a 4.09 in the '20-24 Titan XD with the 9-speed (has a really tall set of overdrive ratios). Nothing wrong with running in 3rd gear. The VQ motor likes some RPM. It has an oil cooler. The basic engine design goes back to the mid 90s. Versions of this engine are used in Z-cars, an alphabet soup infinity cars, well regarded in the engine design. Trying to change the axle ratio is going to still put the engine into the same RPM band, just in a different gear, and make driving without the trailer much worse.