What can cause 1998 cadillac deville cooling fans not to operate

SOURCE: 1999 cadillac deville overheating

my husband did everything that everyone else did that had this overheating problem. It was so weird that my engine cooled at a light and heated up going down the road. I have a north star 4.6 engine and this is natorious for happening. my check engine light also came on and so I had a diagnostics done which told me my #1 injector wasn't firing , car ran like **** as well. After putting in a new water pump and plugs,ect. and realized injector was good a friend told him we could have a blown head gasket. So just to see if this was the problem I went to buy a bottle of glassbeads and the auto parts guy told us to purchase a bottle of BARS STOP LEAK BLOCK SEALER NOT RADIATOR BUT BLOCK SEALER $31.99 . He followed the directions and we waited 24 hrs. before driving it. What ever the problem was has stopped my car runs like brand new and I am loving it again. no over heating no injector problem, runs great.......I hope this helps. I know its probly a temperary fix but its a fix and now we know what the problem was. SASSY

SOURCE: cooling fans not working

you pcm has an open fault it seems to me. Try a used car lot that deals with Cadillacs for most of these used car lots are mechanic owned from the get go

SOURCE: Where are the cooling fan relays for a 1998

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.

SOURCE: location of coolant temp sensor

where can locate the engine coolant temperture sensor.

SOURCE: 1998 cadillac deville fans not coming on starts

If your fans are not coming on then your engine is not receiving the signal that it is overheating. This can be caused by bad fans (unlikely they are both out) a bad relay, or coolant temperature sensor. I would start by checking or replacing the temperature sensor as it can become corroded which is what the PCM uses to turn the fans on. Many vehicles use two sensors, one for the gauge and the other for the ECU, make sure you check/replace the right one. It should be a cheaper part and if you are unsure then match the new one with its location; it should be on the intake manifold or near it, generally with one or two wires. I think you will find your problem as they are common failed parts.

Good luck!