Switchover Valve

1. Check voltage at switchover valve plugs with engine at 1200 ± 50 rpm. Battery voltage should be present.

2. Connect vacuum tester with Y distributor onto switch-over valve top side nipple and check vacuum with engine operating at 1200 RPM and 12 volts applied.
a. On switch-over valve Y27, vacuum readings should be:
Manual trans 300 ± 20 mbar
Automatic trans 350 ± 20 mbar
b. On switch-over valve Y28, approx. 700 mbar (20 in. Hg) of vacuum should be obtained.
c. If vacuum obtained is correct, switch-over valve is satisfactory.
d. If vacuum obtained is incorrect, check vacuum pump and replace switch-over valve if necessary.