Need Help!!!
I Haven't yet had the chance to pull down the 3 book service manual set for the car yet, but have the following problem/issue with the a/c blower system on my 98--
I put the car back in the garage a couple weeks/month ago from the last use and everything was working perfectly. Pulled the car out this past weekend to go fill the tank from the last outing and discovered the the fan blower was inop in any of the A/C-Htr mode functions-- fan blower does not operate at any fan speed, in any of the functions--ie: heater, A/C, Vent, Defrost, Blend, Recirculate, etc. I know the fuses are okay, as during my trip to get gas, while I kept fiddling with all the mode positions, temp and fan position settings, the system kicked in on A/C for all of 30 seconds, and quit just as fast as it came on. How in the H_ _ _ can the system be working when you last use & park the car and then go back in a couple of weeks/month and the system is completely dead??? Nada, nothing, Kaput!!! I don't understand---I have had the car since '02 and this is the 1st problem of any kind I've experienced with this car. Has anyone else had the same or similar problem with the their A/C-Htr system in this gen Riv. Any thoughts, ideas appreciated. I HATE electrical issues. Thanks in advance.

Don,
The fact that it worked before the long rest might be caused by a "visitor" that got into the car and chewed some wires, I would rule that out first.
These years Rivieras had one of two pattern failures, the blower control module and the fan motor. Both are located under the hush panel on the passenger side of the car. Turn the key on , turn the A/C fan on. Disconnect the two wire connector to the fan motor and check for power and ground to the motor. If you have power and ground, the motor is bad. If you have no power, the blower control module is likely the failed component.
HTH,
Tim

From what I have seen on the Reatta website, it is always the blower control module. Three screws, 2 leads to disconnect and about 15 minutes and it's out.

Thanks for the help guys--- had a chance to get out the service manuals and check into the HVAC system---paper trail of checks confirmed your suggestions. Ordered a new blower control module from the dealer -- should have by weekend and hope to have the 98 up operating correctly by the weekend