Problem : Notice the car temp gauge moving up slowly as I idle in traffic upwards .. Get on Freeway it goes down to the reg normal postion Get home
Next Day in AM Cold I let the car warm up to operating temp But Rad fan doesn;t come on at all
I notice both Upper and lower rad hoses are hot The lower one is hotter then the Upper Hose
The car doesn't have a rad cap it is a cap on the overflow jug only That I know of .. And the coolant neither goes up or down ?

So The heater blows and works great gets really hot and when I turn on the a/c the fan still doesn't come on.
I looked at the cooling fan I have only the one and the fuse they were not broken seemed good .. I am not sure where the fan relays are ? there are 3 on the passenger side under the hood but-close to the windshield area not sure if that is the relay ? So I took the plug off the sensor near the thermostat area and the fan now working constantly as as I did that


Any clues to if this the type of 2 in 1 sensor and that operates the gauge on the dash(which stop working as soon as I unplugged it .. and the fan cooling sensor Any help would be grand Thanks
?
1997 Skylark Custom 3.1 liter 4 speed auto

sounds like your sensor is bad, im not real familiar with your car but it sounds like that tells your pcm what the temp is and then the pcm would turn on the fan. open sensor has a saftey for turning the fan all the time, you pretty much checked the rest of the system that way. the only thing i dont understand is why the a/c wouldnt turn it on. also there should be a radiator cap somewhere the systems need pressure to cool and heat effectively. if your cap dosnt have it someone probably broke it off or something.

JW Thanks for the response. much appreciated My friend The rad cap is on the overflow tank it is pressurized cap 15 lbs car only takes dex cool antifreeze this stuff suppose to last like 125000 kms without a change ....
Accordingly the fan should go on to cool the system as soon as the A/C is turned on ..I Just do not have the manual and will look again for a haynes ,, manual on the car ..The 81yr old guy I bought the car from is still looking for the car manual I got about 1 month ago and we had it in the mountains on road trip for about 350 miles .. and no problems at all .. I guess I should replace the thermostat as well and the sensor Someone told me there might be a relay in the fan itself? Im lost at where that would be >

Fan now runs full time after I unplugged the sensor my question is I assume this is a dual sensor for my temp gauge that this sensor controls as well telling the computer to turn on the fan ? Would there be another sensor ? Anyone have a clue to where the relay would be? Thanks again I still miss My 93 SSEi ,,!!!

The PCM looks for a temp via the coolant temp sensor. On our B-villes(might be the same for yours) the low speed fan will turn on at 212F, and the high speed will turn on at 226F. Now, why the PCM is not commanding the fans to turn on while the A/C is on a mystery.

Since you have disconnected the coolant temp sensor, the PCM automatically turns the fans on. This is a built in safety feature to keep the engine cool. So, with this, it appears your fans are working correctly.

If your going to replace the thermostat, I might suggest going with one thats a few degrees cooler than stock. Say, 180. This will keep the engine cooler in the hot summer, and the engine can still reach its normal operating temp for diagnostics to run. Come fall, you can always swap it back for the stock 195.

I have used Rock auto website top look at parts and this shows that the sensor is a dual sensor as in operates my Temp gauge on the dash and the cooling fan
So that is a way other people with these cars can find some info trust me I am not a mechanic a handy man at best My Great grandfather was a master mechanic and owned a garage before I was born ..He worked on Cars since 1920 into the 1970s my father was Mechanic as well and a Stock Car racer .. I love cars but due to a disability I am limited in the work I can do on them (cannot get underneath for 1 example) Sorry off topic there .. ! Anyways I appreciate the response very much I think I will remove the thermostat which I only see 195 rated ones so far but will look for a 180 I ask the auto parts fellows

Stiull have no idea wher the fan relays are what they look like Checking these would be the smart thing to do maybe the reason the cooling temp sensor not working because it partially working sending info to my dash gauge ?

your car has a a/c pressure sensor, the pressure has to build up and the pcm will control the fan. maybe something wrong with that, but you know the fan relay is working because it turns on form the sensor being unplugged. ive never heard of the relay being on the fan itself.

If the fans are coming on when you disconnect the sensor, then the relays are working. We just need to find out why the PCM is not commanding them on during normal operation.

Awesome JW and Mike I thinking the same as you guy I am going to go out double check the a/c but doing a test from the beginning start cold engine with A/C on and sensor plugged in and see if fan comes on from cold ? I might of missed it as I have a 6 yr old lil girl and see has broken foot so I can be distracted ... single parent here !

A/C Compressor Relay might be faulty ?

Where could I post photos of the problem in this thread? is that allowed ?