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SPN 4752 FMI 7 is EGR Cooler Efficiency code. The EGR cooler is plugged or damaged. Careful for if you do clean the cooler or replace it and the code doesn't clear, the front valve can cause this. However, the cooler is the fault 95% of the time.
SPN 412 FMI 5 EGR Temp high. Sever Level. This is related to the cooler.
SPN 412 FMI 15 EGR Temp high, least severe level. Again, due to the cooler.
On the air bags, see if you are getting power to the dump valve from the switch when you change the switch over. You didn't write a code for it so I'm presuming the switch is good and the signal is being sent. The issue will be in the air valve/electrical solenoid for the air bag dump.
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