Disconnect vacuum hose 26 from the vacuum manifold.
Connect the vacuum pump and create a vacuum.
Turn the ignition key to the START position.
ATTENTION! The coolant temperature must be below 40°C.
If the vacuum remains at the same level, then see point A). If not, then point B).
A) Turn off the ignition.
Disconnect the 8-pin connector on the control box.
Measure the voltage between the Blue/Red (+) and Black (-) terminals on the main wiring harness.
Turn the ignition key to the START position.
If there is battery voltage, then the solenoid valve should be replaced.
If there is no voltage, then measure the voltage between the Blue/Red (+) contact and ground with the ignition key in the START position.
If there is battery voltage, then the break in the Black conductor between the control box and point G7 should be corrected.
If there is no voltage, then you should check for a break in the Blue/Red wire between the control box and terminal 27 of the control unit. If the wire is normal, then you should refer to the section on diagnostics of control module inputs.
B) Start the engine and allow it to warm up to operating temperature until the cooling fan comes on.
Create a vacuum.
If the solenoid valve holds vacuum, the vacuum line should be checked for proper connection, cracks, plugs, or a disconnected hose.
If the valve does not hold vacuum, then the 8-pin connector on the control box should be disconnected.
Next, measure the voltage between the Blue/Red (+) and Black (-) terminals in the main wiring harness.
If there is voltage, then you should refer to the section on diagnostics of control module inputs.
If there is no voltage, then the solenoid valve should be replaced.
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