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Home › Ford › 1985 › Cutaway 6.9 1 › Repair and Diagnosis › Engine Performance › System › Fuel Injection System - 6.9L Diesel › Testing › Glow Plug Test B Test Lamp On Continuously

Glow Plug Test B Test Lamp On Continuously

NOTE: Ford has updated it's Glow Plug Testing procedures please see TSB 88-11-19 in the TECHNICAL SERVICE BULLETIN Section.
  1. Disconnect all leads from glow plugs and do not reconnect until after system has been checked for proper operation. Connect a 12 volt test lamp to glow plug power relay output and ground. Turn ignition on, but do not start engine. If test lamp cycles but "GLOW PLUG" light in dash does not, repair or replace circuit wiring to light, or replace bulb, as needed. Repeat GLOW PLUG SYSTEM TROUBLE SHOOTING  . If test lamp does not turn off, proceed to step 2.
  2. With test lamp still connected, turn ignition on. Disconnect wiring harness from control switch. If test lamp goes out, replace control switch and repeat GLOW PLUG SYSTEM TROUBLE SHOOTING  . If test lamp does not go out, proceed to step 3.
  3. With test lamp still connected, turn ignition on. Disconnect engine harness from chassis harness. If test lamp goes out, replace engine harness and go to step 7. If lamp stays on, go to step 4.
  4. Turn ignition off. Disconnect signal lead from power relay. Turn ignition on. If test lamp goes out, repair or replace chassis harness as needed and go to step 5. If lamp stays on, go to step 5.
  5. Turn ignition off, remove test lamp and disconnect battery lead from power relay. Reconnect test lamp. With power relay output lead still connected, turn ignition on. If test lamp remains on, repair or replace chassis wiring harness to glow plugs. If lamp goes out, replace power relay.
  6. With ignition off, remove test lamp from power relay and reconnect all leads (EXCEPT glow plugs). Check continuity from each glow plug lead to power relay output. If resistance is less than 1 ohm for all glow plugs, go to step 8. If resistance is 1 ohm or greater for 1 or more glow plugs, go to step 7.
  7. With ignition off, disconnect engine harness and chassis harness fusible links from chassis harness. Check resistance of all fusible links. If resistance of all links is less than 1 ohm, replace engine harness. If resistance of one or more fusible link is 1 ohm or greater, replace link and repeat step 6.
  8. With ignition off and engine harness disconnected at glow plugs, check resistance between each glow plug terminal and metal shell of glow plug. If resistance is less than 2 ohms for all plugs, glow plug system is OK. Reconnect engine harness to glow plugs and repeat GLOW PLUG SYSTEM TROUBLE SHOOTING  . If resistance for any plug is 2 ohms or greater, replace glow plug(s). Reconnect engine harness to glow plugs and repeat GLOW PLUG SYSTEM TROUBLE SHOOTING  .
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