It's common for the EGR valve to fail on this engine, however, the hoses do have to be checked, and that vacumme is present at the EGR from the electrical solinoid valve. The quickest test you can do is apply vacumme from a manual vacumme pump (sold at most parts suppliers, fairly inexpensive). If the valve does not hold vacumme, or hold vacumme but the engine doesn't run rough while the vacumme is applied, the valve is bad. This valve lists for approx. $280.00. You should be able to find it in the aftermarket for slightly less. The EGR system is used to cool combustion temperatures, which in turn reduces Nox emmisions (Nitrous-Oxides). So without the EGR sytem working properly, the engine may "ping" under loads, and fail smog, and or ruin the catalyst if the repair is prolonged over a long time. The valve is simple to install yourself, if your mechanically inclined which might save you some labor time.

On the climate control condition, it trully needs corect diagnosing; but it sounds like the typical failure of the Control Head Unit. The problem here is the Control Head list price between $380.00-$420.00! There is very little used ones out there due to there common failure, and most units available are rebuilt. You may want to search the internet for possible inexpesive units. Try Ebay, they come on there from time to time. Another common failure on these that causes constant heat is the mono valve or heater valve which will get stuck open and circulate hot coolant thru the interior.

-Rip