The front an rear are two different systems , That why the back still works . The blower motor or the resistor under the glove box or behind burnt up . Your best bet mite be to take your vehicle to a qualified repair shop.
fuel gauge the tank sender is like a resister, no resistance to ground gauge goes up, i think you have a grounding fault in the earth wire, you will need to trace were the wire goes to or make a new feed, making a new earth feed can sometimes be better if you have a spare bulb and some wire to attach to it connect one wire to the live feed on the pump and then ground the earth wire on the shell if it lights up then its the ground that's at fault.
The PCM does not supply the voltage to the fuel pump . All the PCM does is energize the fuel pump relay ,closing contacts in side the relay which connects the fuel pump with a B+ voltage supply from Fuel pump fuse 15amp location , under hood fuse box . You have a high resistance problem in the wiring to the fuel pump . bad connection , corrosion etc... Mastering Voltage Drop Testing with Pete Meier and Jerry Truglia
Take it to a ASE certified repair facility ,they'll fix it up ! Don't just replace parts !!!!!
P0171 - is a lean code bank 1 -possible vacuum leak , low fuel pressure , plugged fuel filter ,
P0300 - is a random misfire code which is understandable with a lean code .
P0420 As the code description implies the P0420 code means that the vehicle's control module has detected that the three-way catalytic converter is not working properly (is not as efficient as the factory is expecting). Replacing the oxygen (O2) sensors may sometimes fix the code, but in most cases the catalytic convert needs to be replaced to fix the problem. If the P0420 code is combined with other codes, try fixing the other codes first
P0452 - EVAP Control System Pressure Sensor Low Input
P0446 - Evaporative Emission Vent System Performance
P0453 - Fuel Tank Pressure Sensor Circuit High Voltage
P1639 - PCM 5 Volt Reference Voltage Circuit Condition
P1653 - Power Steering Output Circuit Malfunction
P1651 - Fan 1 Relay Control Circuit
If you don't know what your doing take it to a repair shop before you waste your money ! You have a lot of problems here an I don't think the computer is bad , I'd say lack of maintenance ! You need to learn how to test thing's to fix them ! From the five volt reference voltage code , I'd say one of your sensors is shorted internally bring down the ref. voltage circuit causing the no start, but then again the 5volt ref. circuit in the PCM could be the problem . What you need to do is Disconnect all sensors that receive 5volt ref. signal one at a time an see if it will start . If I knew what year vehicle yours is I could tell you what sensors ! MAP, TPS , etc...
You can have a new ignition barrel put in the car. This would come with new ignition keys. You might be able to get replacements from a dealership as well.
Remove the electrical/fuse box. Just pops off. Remove the bar that goes across the battery. Remove the terminals and remove the hold down bolt that secures the battery. You need an 8 MM wrench(5/16ths) And a 13 MM socket with ratchet.
