|
PROBLEM
|
PROBABLE
CAUSE
|
SOLUTION
|
| I.
Air leaking from fan drive bleed hole |
1.
Bad seals or air cartridge.
 |
1.
Install repair kit. |
| II.
Premature friction lining failure |
| 1.
Obstructed fan. |
|
2. Low air pressure to fan drive. |
|
3. Excessive cycling. |
|
|
| 1.
Loose shroud, bent fan, torn engine mounts, etc. |
|
2. a. Restricted air line. |
|
b. Restricted solenoid valve. |
| c.
Low system air pressure. |
| d.
System air leak. |
|
3. a. A/C freon overcharge. |
|
b. A/C pressure switch setting too low. |
| c.
Poor ground or wire connection. |
| d.
Improper temperature control setting. |
|
e. Faulty ECM. |
| f.
Faulty thermal switch. |
|
g. Restriction in front of radiator blocking air flow. |
| h.
Faulty air-temp switch. |
Air
Problem
|
|
1. Solenoid valve not exhausting or engaging properly. |
|
|
| 1.
Find and remove obstruction, repair or replace damaged parts.Install
repair kit. |
|
2. a. Replace air line. Install
repair kit. |
| b.
Replace solenoid valve. Install repair kit. |
|
c. Repair system. Install repair kit. |
|
d. Repair leak. Install repair kit. |
|
3. a. Check and adjust to specifications. |
|
b. Check A/C pressure switch. |
|
c. Check electrical connections. |
|
d. Check temperature setting of all controls. Thermal switch
setting should engage the fan drive 10fF higher
than the full open temperature of the thermostat. |
|
e. Check ECM. |
| f.
Replace the thermal switch. |
|
g. Check for proper shutter operation, winter front or other
restriction in or in front of the radiator. |
|
h. Replace the air-temp switch. |
|
| 1.
Check for plugged exhaust/intake port on the solenoid valve.
Clean or replace the solenoid valve. |
|
| III.
Fan Drive fails to engage/disengage |
Electrical
Problem
|
|
1. Open/shorted circuit. |
|
2. Improperly wired. |
|
3. Thermal switch incorrect for application. |
|
4. Failed solenoid valve. |
Air
Problem
|
|
1. Air line restricted. |
|
2. Solenoid valve defective.
|
Piston
will not actuate
|
|
1.
Piston seized due to contamination or dry seals.
|
|
|
| 1.
Check electrical connections. |
| 2.
Check wiring according to diagram |
|
3. Check thermal switch application. Replace if wrong or
defective. |
|
4. Replace the solenoid valve. |
|
| 1.
Check air line from solenoid to fan drive for kinks or obstructions. |
|
2. Replace the solenoid valve. Check to see if air exhaust
is restricted.
|
|
|
1.
Clean the air supply and install a rebuild kit.
|
|
| IV.
Fan drive cycles frequently |
Electrical
Problem
|
|
1. Poor ground wire connection. |
2. Improper temperature control settings.
|
|
3. A/C pressure switch setting too low. |
|
4. Restriction in front of radiator, blocking air flow. |
|
5. Faulty thermal switch. |
|
6. Faulty air-temp switch. |
|
7. Vehicle coolant level too low. |
|
|
| 1.
Check electrical connections. |
| 2.
Check temperature setting of all controls. Thermal switch
should engage the fan drive 10o F higher than
the full open temperature of the thermostat. |
|
3. Check A/C pressure switch. Use higher switch. |
|
4. Check shutter operation, winter fronts, or obstruction
in front of radiator. |
|
5. Replace the thermal switch. |
|
6. Replace the air-temp switch. |
|
7. Fill to manufacturer's recommended level. |
|
| V.
Fan drive engaged, engine running hot. |
| 1.
Restriction in front of radiator. |
2. Fan capacity not large enough.
|
|
3.
Problem in cooling system.
|
|
| 1.
Make sure nothing is obstructing the airflow through the
radiator. |
2. Refer to specifications.
|
|
3. Refer to engine manual. |
|
