Cruise Control - Set Function Inoperative
90saab08Subject: Cruise Control Switch Modification
Application: Certain 1990 9000 Models
CATEGORY Electrical
SECTION PAGE
3 5
ISSUE CODE
12/90-0075 391
Incorrect adjustment of the brake or clutch switches can cause the cruise control system to be inoperative. Typically the customer complaint is that the cruise control speed set function does not work. The brake and clutch switches (both switches are identical) were modified beginning with 1990 models to incorporate a self-adjusting ratcheting mechanism. This ratcheting mechanism can sometimes over-adjust (ratchet too far in) preventing the pedal from depressing the switch's pushrod actuator when the pedal is at rest, leaving an open circuit in the switch.
A procedure has been developed to modify the switch to increase the tension on the adjusting mechanism. Before carrying out this procedure on cars with manual transmission, however, the clutch pedal operation should be checked to make sure it is returning completely (see PSI 07/90-0012). If one switch on a car with manual transmission requires modification, the other switch should also be modified at the same time.
Figure 1:
Parts Required:
3/8 in. ID heat shrink tubing Local Supply
Switch Modification Procedure
1. Remove the lower dash panel.
2. Set the pushrod in the pedal switch to the correct position by depressing the pedal, pulling the switch pushrod out and then returning the pedal to its rest position.
3. Disconnect the vacuum hose and the connector from each pedal switch and remove the switch(es).
4. Carefully separate the two halves of the switch using small screwdrivers to release the four catches (see Figure 1). Do not use excessive force when releasing the tabs or they may break. As an aid, a feeler gauge blade may be inserted under the tab so it will remain released after the screwdriver is removed.
NOTE
Do not after the setting of the pushrod in the selfadjusting mechanism while the switch is disassembled.
Figure 2:
5. Remove the pushrod assembly.
6. Fit a 10 mm (7/16 in.) long piece of 9.5 mm (3/8 in.) inside diameter heat shrink tubing over the spring-loaded portion of the pushrod (Figure 2).
7. Carefully shrink the tubing using a hot-air gun. Allow the pushrod assembly to cool.
Figure 3:
8. Reassemble the switch and check that the pushrod slides freely (Figure 3).
9. Reinstall the switch(es) in the mounting bracket.
10. Reconnect the vacuum hose(s) and also the connector(s) to the switch(es).
11. Test drive the car and check that the cruise control system is working correctly.
12. Reinstall the lower dash panel.
Warranty Information:
For warranty claims, use Failure Coding 36854-79-0-01-05. Time allowance is Labor Operation No. 36854 (0.3 hour) plus 0.1 hour straight time for M/T cars (two switches).