01-153
 
     
Rear window heating, 
electrical testing 
     
Note:  
     Only perform this test on A/C control heads -E87- 
with only one display (switch for rear window 
heating is integrated in the A/C control head -
E87-). 
     
Special tools and equipment  
     
VAG1715 multimeter (with voltage probe)
     VAG1594A Measuring Appliance Adapter
     
Test requirements 
     All fuses OK 
     
       Electrical Wiring Diagrams, Troubleshooting & 
Component Locations binder   
     
-  Switch ignition off.
     
-  Remove A/C control head -E87-   page 87
-
120
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        01-155
      
- Start engine. 
     
-  Switch rear window heating on via A/C control 
head -E87- (indicator lamp in button lights up). 
     
   Specified value: The display on VAG1715 will 
change from approx. 0 amps to less than 25 
amps. 
     
-  Wait approx. 10 minutes.
     
   Specified value: The display on the VAG1715 
will change from less than 25 amps to approx. 0 
amps (indicator lamp in button goes out). 
     
Notes:  
     
The current probe may be influenced by stray 
current which could cause the display to show a 
low current reading when rear window heating 
is switched off. 
     The A/C control head -E87- will switch rear 
window heating off after 10 minutes. 
     When the outside temperature is less than 0 C 
the heating function of the rear window will 
remain on until the ignition is switched off (it can 
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