BMW Coupes and Sedans 1970-1988 Repair Guide

Temperature Timing Switch

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See Figure 1



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Fig. Fig. 1: Cut-away view of a temperature timing switch

The purpose of the timing switch is to control the cold start valve during the initial start-up of the engine. The function temperature range of this switch is between -4°F (-20°C), where it turns ON , and 95°F (35°C), where it turns OFF .

TESTING



  1. Disconnect the terminal plug from the switch.
  2.  
  3. Connect a test lamp from the positive battery terminal to the W post on the temperature timing switch.
  4.  
  5. The test lamp should be on at coolant temperatures below 95°F (35°C) and go out above temperatures of 95°F (35°C).
  6.  

REMOVAL & INSTALLATION



  1. Disconnect the wire harness attached to the switch.
  2.  
  3. Unscrew the switch. Some coolant will spill out, so place a container under the engine to catch any coolant.
  4.  

To install:
  1. Screw the switch in until the crunch washer is squeezed.
  2.  
  3. Connect the harness.
  4.  

 
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