1987 Honda Prelude Base, AutomaticFACTORY OEM SERVICE PROCEDURE

Switch C

Disconnect No. 15 hose from control box at vacuum hose manifold. Connect vacuum pump to hose. Check for continuity between Black/Yellow wire and Blue/Black wire terminals of control box connector. There should be continuity when more than 1.2 in. Hg vacuum is applied to switch. There should be no continuity when vacuum is released.

Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.

When to See a Mechanic

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

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