Welcome to the forum. I believe you have the system where you turn a dial type knob to access 4H, 4L and 2H… yes?
Assuming you just said yes, this is what may have happened or is still happening. Sometimes the system does not fully switch the xfer case into the range mode you or someone else prior had selected, they may not have switched it properly…or some such issue occurs and is never sorted out. Sometimes the xfer case gets sort of stuck in between modes or the encoder does not know which mode it is in currently.
I would do this just to see where things stand and to see if it responds correctly to your inputs. That knob is not supposed to be turned until you are in Neutral…not sure if you are aware of that…but that IS the case here. So start her up, drive to a suitable spot that will allow you to move the vehicle…dirt road is actually preferrable here as you cannot engage 4L and turn the front wheels unless you are on a very slippy surface…so if on tarmac…do NOT turn your front wheels left and right at all.
Drive to a spot like an empty lot or what have you… Go into neutral and select 4H…move the vehicle forward n backward…stop… Neutral again… and try for 4L…move forward n back… then stop, Neutral and then go backward towards 2H again…by going into 4H again (using neutral each time)…and then go into 2H (neutral whenever you touch that knob remember)…and then drive around normally.
Did the xfer case do as it was told so far as you can tell? Hopefully it did…now you just need to see what happens driving in 2H without messing with the knob again. What you would have accomplished with this little test is to have walked your xfer case through all of its operational ranges in the correct way. This was not only to see if it could do it, but to also make it go from 2H…all the way through every option…and back home to 2H again 9basically trying to positively engage its home position in 2H…after being in all other modes). If the case was not fully in its home position before, hopefully it is now. See what you get and report back. I’d stay in 2WD and drive normally…hopefully it does not do what it did prior like selecting 4H or L without you asking…the way that can happen is if the case is not positively shifted or the encoder doesnt park the xfer case shifter exactly where it should be (its adjustable btw)
Turning the key and no start sometimes? Look at your dash when this is happening…do you notice a security or alarm icon illuminated? It may be doing this no start on purpose… If you have another key use the other key when it is difficult to start…or…just begin to pay attention to which key you are using at all times…and see if the no starts are only associated with one key over the other… This is to suss out any security issues with the key and its chip itself.
No ventilation fan action? I dont know if that motor is fused via the fuse panel (usually its fused by something called a fuseable link)…but you can look into that possibility…see if it is fused in the normal fuse panels and check the fuse condition (I think its fused via F-Links however). If it is not fused traditionally just move forward and unplug the blower motor. Using a digital volt meter…measure voltage at the plug when you turn the switch on, cycle thru all speeds and measure, see what you get. If you have power at the plug, then its the blower motor itself… if you do not have power it can be the motor speed switch, the fuseable links that protect the motor or the blower motor resistor (which gives you the motor speeds).
You need to do a little troubleshooting. It shouldn’t be difficult to locate and remove the blower motor…it is in the passenger side down by the foot well…usually behind the glove box…which you can open all the way to access the motor. Sometimes turning the motor by hand frees it up and makes it work again and or it lets you see the condition of the motor a bit by testing how it spins…freely or not.
That’s about it… Sorry to you and all for writing you a book here