Ventola radiatore lato guida non si accende

[wranglertexan]

Ciao, in queste settimane ho riscontrato un problema intermittente sulla mia LT1 '94. Con il climatizzatore acceso e temperatura esterna elevata, talvolta il ventolone lato guida non si accende. Quello lato passeggero invece funziona normalmente. Se spengo il clima non cambia nulla...
Questo inconveniente fa sì che, in colonna, la temperatura vada fuori controllo, anche oltre i 110 gradi.

Ho fatto un veloce test alla ECM e non segnala nessun errore, quindi i relay dovrebbero essere ok.
Ho guardato i fusibiloni nel vano motore e anche quelli sono ok.
Cosa potrebbe essere? è possibile collegarla in maniera diretta, finchè non identifico il problema? in modo da stare più tranquillo... se sì come?

grazie mille

[oVoSanto]

Guarda se nei paraggi di ogni ventola del radiatore hai una roba così:


E' una resistenza di protezione con termofusibile messa in serie alla ventola. Serve per evitare corti quando si blocca il motorino o sforza troppo. Però occhio che se è saltata (verifichi mettendo il tester in ohm fra i 2 faston) significa che hai un problema di ventilatore. A mano gira libero o senti che sforza?

[wranglertexan]

dopo provo a verificare girandola a uoto, ma non credo che sia questo il problema, dato che a volte funziona e a volte no

[oVoSanto]

Probabilmente allora sarà un falso contatto su qualche connettore...

[lastout]

probabilmente ossidato

[wranglertexan]

quali connettori mi consigliate di verificare?

[Force V8]

Ma la mia spesso parte a 110 gradi, hai provato ad aspettare ancora un po?
E' anche vero che la centralina ordina l'accensione della ventola anche in base ad altri parametri, ed ultimamente con questo caldo mi sembra che abbia abbassato a 104°.

[bluesman]

ho trovato questo su un forum americano......


If you are the same as a '90:

Cooling Fans 101 (Earlier Post)

The '90 L98's ECM controls both the primary and secondary cooling fan relays.

Fans are used to cool engine coolant flowing throught the radiator and to cool refrigerant through the A/C condensor.

Control is by ECM ground path to the fan relays. Relays control the 150 watt motors that drive the five blade, 299mm (11.77") diameter fans. The ECM determines operation of the independent fans based on the A/C head pressure & request signal inputs, ENG coolant/oil temperature, and vehicle speed.

Primary Cooling Fan #1
The fan is totally controlled by the ECM based on inputs from:

ON:
A/C request signal: (YES)
A/C fan request signal: (YES-High A/C PRESS)
Coolant Temp Sensor (CTS): (>108C/226F)
Vehicle Speed Sensor (VSS): (<35mph)

OR:
A/C request signal: (NO)
Coolant Temp Sensor (CTS): (>108C/226F)
Vehicle Speed Sensor (VSS): (>35mph)

OFF:
Conditions met for 20 seconds
A/C request signal: (YES)
Coolant Temp Sensor (CTS): (<105C/221F)
Vehicle Speed Sensor (VSS): (<35mph)

OR:
A/C request signal: (NO)
Coolant Temp Sensor (CTS): (<105C/221F)
Vehicle Speed Sensor (VSS): (>35mph)

Secondary Cooling Fan #2:
The fan is controlled by the ECM based on inputs from the CTS & VSS. The ECM will only turn the secondary fan ON if the primary fan has been ON for 2 seconds and the following have been met:

ON:
A/C fan request signal: (YES-High A/C PRESS)
Vehicle Speed Sensor (VSS): (<50mph)

OR:
A/C request signal: (YES)
Coolant Temp Sensor (CTS): (>113C/235F)
Vehicle Speed Sensor (VSS): (<35mph)

OR:
A/C request signal: (NO)
Coolant Temp Sensor (CTS): (>113C/235F)
Vehicle Speed Sensor (VSS): (>35mph)

If both fans are ON, the ECM will turn OFF the secondary fan after 15 seconds of the following conditions:

OFF:
Conditions met for 20 seconds
A/C request signal: (YES)
Coolant Temp Sensor (CTS): (<108C/226F)
Vehicle Speed Sensor (VSS): (<35mph)

OR:
A/C request signal: (NO)
Coolant Temp Sensor (CTS): (<108C/226F)
Vehicle Speed Sensor (VSS): (>35mph)

[CSM, 1990, 6E3-C12-1,2]

I'd expect your '95 to be the same, or very close to the '90.

To verify fan at speed, I'd run a temporary 12v lightbulb circuit, tapped into the fan motor connectors. The light comes on when the fan relay energizes the motors.

[wranglertexan]

Ma la mia spesso parte a 110 gradi, hai provato ad aspettare ancora un po?
E' anche vero che la centralina ordina l'accensione della ventola anche in base ad altri parametri, ed ultimamente con questo caldo mi sembra che abbia abbassato a 104°.

Era arrivata a 115! Mi viene un dubbio...dato che la ventola primaria dovrebbe essere quella lato guida...non è che qualcuno in passato ha invertito i relay??
Grazie blues per la ricerca...una complessità pazzesca! comunque date le condizioni dovevano accendersi entrambe!

[tunedport]

ho trovato questo su un forum americano......


If you are the same as a '90:

Cooling Fans 101 (Earlier Post)

The '90 L98's ECM controls both the primary and secondary cooling fan relays.

Fans are used to cool engine coolant flowing throught the radiator and to cool refrigerant through the A/C condensor.

Control is by ECM ground path to the fan relays. Relays control the 150 watt motors that drive the five blade, 299mm (11.77") diameter fans. The ECM determines operation of the independent fans based on the A/C head pressure & request signal inputs, ENG coolant/oil temperature, and vehicle speed.

Primary Cooling Fan #1
The fan is totally controlled by the ECM based on inputs from:

ON:
A/C request signal: (YES)
A/C fan request signal: (YES-High A/C PRESS)
Coolant Temp Sensor (CTS): (>108C/226F)
Vehicle Speed Sensor (VSS): (<35mph)

OR:
A/C request signal: (NO)
Coolant Temp Sensor (CTS): (>108C/226F)
Vehicle Speed Sensor (VSS): (>35mph)

OFF:
Conditions met for 20 seconds
A/C request signal: (YES)
Coolant Temp Sensor (CTS): (<105C/221F)
Vehicle Speed Sensor (VSS): (<35mph)

OR:
A/C request signal: (NO)
Coolant Temp Sensor (CTS): (<105C/221F)
Vehicle Speed Sensor (VSS): (>35mph)

Secondary Cooling Fan #2:
The fan is controlled by the ECM based on inputs from the CTS & VSS. The ECM will only turn the secondary fan ON if the primary fan has been ON for 2 seconds and the following have been met:

ON:
A/C fan request signal: (YES-High A/C PRESS)
Vehicle Speed Sensor (VSS): (<50mph)

OR:
A/C request signal: (YES)
Coolant Temp Sensor (CTS): (>113C/235F)
Vehicle Speed Sensor (VSS): (<35mph)

OR:
A/C request signal: (NO)
Coolant Temp Sensor (CTS): (>113C/235F)
Vehicle Speed Sensor (VSS): (>35mph)

If both fans are ON, the ECM will turn OFF the secondary fan after 15 seconds of the following conditions:

OFF:
Conditions met for 20 seconds
A/C request signal: (YES)
Coolant Temp Sensor (CTS): (<108C/226F)
Vehicle Speed Sensor (VSS): (<35mph)

OR:
A/C request signal: (NO)
Coolant Temp Sensor (CTS): (<108C/226F)
Vehicle Speed Sensor (VSS): (>35mph)

[CSM, 1990, 6E3-C12-1,2]

I'd expect your '95 to be the same, or very close to the '90.

To verify fan at speed, I'd run a temporary 12v lightbulb circuit, tapped into the fan motor connectors. The light comes on when the fan relay energizes the motors.

questo post e' oro colato,vedete che i forum americani servono...non c'e'nulla da dire... sanno il fatto loro:questa e' la risposta competente che ci si aspetta da un membro del forum.