We need to know were the cooling fan control switch is located on a 1997 cadillac sadan deville.

They are between the fans behind radiator.

I am not familiar with Cadillac, however I have not experienced such an option for electrical fans as they are run off of temp sensors. I suggest contacting a Cadillac dealership, or the manufacturer themselves.

SENSOR ON NORTHSTAR V8 IS ON DRIVERS SIDE OF MOTOR RIGHT ABOVE TRANSMISSION. COOLING FAN RELAYS ARE UNDER FANS ,IN MIDDLE OF LOWER CROSSMEMBER

Check the fan to see if it is going on. On my 1997 Cadillac Deville Limousine I had to have the 2 fans, and 3 relays replaced, as well as the wiring contacts for the relays at an auto electric shop for about $700 last fall, but it has been running cool since then.

I read on RepairPath.com that the coolant temperature sensor is located on the left side of the engine down below the panel that holds the fuses and below the cruise control on the 'left' hand side. It screws in to the manifold, I believe.

the vents that receive the blowing air is of course provided by the blower motor. The duct work the blown air goes through has doors that open & close for the direction you want the heated air to be directed to. A motor runs these doors so you may have a bad motor to the main door

Oil pressure switches a normally located by or near the oil filter on all cars. :-)

Are you sure that you don't mean the cooling fan control module? It should be located up front next to the cooling fan. It is square shaped and has a long square shaped plug going into it. Reads the temperature of the coolant and passes the information to the engine control computer (ECC). The ECC receives analog information and signals the cooling fan switch to cycle the cooling fan on or off, as required.

What makes you think its the relays ? How about THE FANS themselves, or the coolant switch that tells the electric fans when they should turn on. Test his procedure. Place the climate control on AUTO at 65. A/C compressor turn on ? Did the COOLING FANS tun on ? If they did , at least you know they work. Hope this helps.