Relay unit, radiator fans (706a), Z19
 
  
 
 
  
   
    
     | 
      | 
     
      Relay unit, radiator fans (706a), Z19
      | 
    
   
  
  
  
   Relay unit containing relays and resistors and thermal fuse.
   
   
   
   
   
   
   
  
  
   
   
    
     
     
     
    
    
     
      | 
       
        
         Pin No.
        
       
       | 
      
       
        
         Signal type
        
       
       | 
      
       
        
         Description
        
       
       | 
     
     
      | 
       
        3
       
       | 
      
       
        +30
       
       | 
      
       
        Power supply 37RH from fuse holder 748.
       
       | 
     
     
      | 
       
        6
       
       | 
      
       
        +30
       
       | 
      
       
        Power supply 37LH from fuse holder 748.
       
       | 
     
     
      | 
       
        2
       
       | 
      
       
        Power ground
       
       | 
      
       
        Grounding of 37LH in grounding point G2.
       
       | 
     
     
      | 
       
        5
       
       | 
      
       
        Power ground
       
       | 
      
       
        Grounding of 37RH in grounding point G2.
       
       | 
     
     
      | 
       
        1, 4 and 7
       
       | 
      
       
        Control. Ground= active
       
       | 
      
       
        Grounded by the ECM. The pins are grounded differently depending on current fan stage, see table below.
       
       | 
     
    
   
   
   
  
  
   
   
   
    Connection stage
   
   
    
     
     
     
     
    
    
     
      | 
       
        
         Stage
        
       
       | 
      
       
        
         Pin 7
        
       
       | 
      
       
        
         Pin 4
        
       
       | 
      
       
        
         Pin 1
        
       
       | 
     
     
      | 
       
        1
       
       | 
      
       
        grounded
       
       | 
      
       
       
       | 
      
       
       
       | 
     
     
      | 
       
        2
       
       | 
      
       
       
       | 
      
       
        grounded
       
       | 
      
       
       
       | 
     
     
      | 
       
        3
       
       | 
      
       
        grounded
       
       | 
      
       
        grounded
       
       | 
      
       
       
       | 
     
     
      | 
       
        4
       
       | 
      
       
        grounded
       
       | 
      
       
        grounded
       
       | 
      
       
        grounded
       
       | 
     
    
   
   
   
  
  
   In stage 1 the fan motors are connected in series and supplied with voltage via pin 6.
   
   
  
  
  
   
    
     
      | 
       •
       | 
      
       Power supply
        
        
       
         
       
        
       | 
     
    
   
  
  
   
    
     
      | 
       •
       | 
      
       Control
        
        
       
         
       
        
       |