1985 Mazda GLC BaseFACTORY OEM SERVICE PROCEDURE

Vacuum Switch

  1. The 3 vacuum switches are located on the firewall behind the carburetor. The individual switches can be identified by wiring color code of electrical connector. Unplug electrical connector and vacuum hoses.
  2. Connect a vacuum source and circuit tester to each valve and check their calibration.
  3. On No. 1 switch, connect a circuit tester to Blue/Red and Green/Yellow terminals. The switch should be off at .8 in. Hg and on at 4.3-5.1 in. Hg.
  4. Connect circuit tester to Blue/White and Green/Yellow terminals. The switch should be off at .9 in. Hg and on at 7.5-8.3 in. Hg. No. 3 switch has same color codes and is tested in the same manner.
  5. On No. 2 switch, connect circuit tester to Yellow/Green and Black terminals. The switch should be off at 1.2 in. Hg and on at 13.8-15.4 in. Hg.
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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