Grid Filament Test

2000 Saturn LW1 AutomaticSECTION Grid Filament Test
  1. Start engine. Turn defogger on (press and release rear defogger switch button once). Using grounded test light, lightly touch each grid line. If test light shows full brilliance at both ends of all grid lines, check for loose ground wire. Test light brilliance should gradually change as test light probe is moved from one side of grid to the other.
  2. Contact each grid line a few inches on either side of glass center line to eliminate possibility of missing a break in grid line. If a problem on a grid line is detected, place test light probe on grid line at power bus bar and move probe toward ground bus bar until light goes out, indicating a break in grid line continuity. See Fig 1 . If break exists in grid line, go to GRID FILAMENT REPAIRΒ  under ON-VEHICLE SERVICE.
Fig 1: Examining Grid Brilliance Test Patterns
G95D14640Courtesy of GENERAL MOTORS CORP.
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

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

Affiliate disclosure: We may earn a commission at no extra 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.