Hello !

First of all thanks to those who help many people on this forum.

I have a problem on my Cad Seville STS 1994.
Cooling fans (small and high speed) no longer work when the automatic box heats up too much and the engine temperature exceeds 95 ° C (203 ° F)

I changed the thermostat, temperature sensor, checked the relays of the fans and fuses, checked the water pump and all that is ok. I do not have a permanent code just from the historical ones that are no longer.

I am overwhelmed and can not find the problem !!!

Can you help me please !!!!!


Jonathan,

 

Cooling fans should come on with A/C or when engine temp reaches 226* and will quit approx. 210*. Codes should set if there is a fan failure. Typical engine operating temperature range is 190-215 and possibly up to 230 in stop and go traffic in 90*+ weather.

 

Thanks for your slowroll response. I tried with A / C and no fans worked. I let the engine temperature rise to 224 ° F (107 ° C) and the fans did not work.
The low speed of the fan must also activate when the automatic transmission fluid is too hot but the latter does not lock.
I remember before the low-speed fan snapped around 185 ° F (85 ° C) to cool the automatic gearbox fluid and the high speed at 204 ° F (96 ° C). I am afraid to make a cylinder head gasket by letting it rise in temperature. P.S: If I put A / C on cold, should the fan start after 2 seconds or wait longer? Thank you in advance...

 

Also I disconnected the battery for 3 months and when I reconnected it I launched the
computer on board to see the error codes following the reconnection of the battery.
But after making a clear codes I have that history

 

After all this period without battery, do you have to do a reprogramming
for the PCM / ECM?

 

No programming required, however Idle maybe a little off for the first few times you drive car until idle is learned. you may or may not notice it. car has on-board functions as well as OBD. Get the 2 volume FSM and there will be info to fix most things without going to dealer or service shop. It is possible to use the override features to check fan operation.

 

Thanks slowroll for the lights.

I will take the 2 FSM and see if I find my happiness.
In France the garages are not friendly and do not want to do a test with OBD.

And even a garage that sells American cars does not want so I have to fend for myself ... If I find the breakdown I would come back to inform but it may take time ... Otherwise I think the PCM / ECM is HS but without OBD ... Finally ... See you soon,

 

Even in the states there are people who don't want to deal with pre 1996 cadillacs. Good Luck!

 

Hello !

Slowroll I turned on the air conditioner to see if one of the two fans was activated but nothing and after the temperature exceeded 222.8 ° F (106 ° C) the low speed is switched on !!

I still cut the cilm to see if the fan would still turn and it turns. When it was stopped the temperature was 212 ° F (100 ° C) and I let the temperature go up to see if the fan would go off without the A / C mode and it would turn !! You were right and I thank you greatly :-) !!

Good day and thanks again for your advices :-) :-) !!!