1987 Jeep Cherokee LimitedFACTORY OEM SERVICE PROCEDURE

Glow Plug System

Engine starting is aided by an electric glow plug system. Glow plugs are small heaters that assist in cold starting. A glow plug is threaded into each cylinder combustion chamber. This system pre-heats each combustion chamber to aid ignition of fuel.

System consists of 4 glow plugs, control switch, timer, and a wiring harness which incorporates 4 fused wires (one for each glow plug) located between wiring harness and glow plug terminal.

The glow plug controller and relay cycle 12 volts to these 6-volt heaters, which causes them to heat rapidly. After engine starts, glow plugs remain on between 4 and 10 seconds during initial starting cycle.

Factory Service Tools

Use the Manual With the Right Hardware

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

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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.

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