S10/T10 Blazer 2WD L4-137 2.2L DSL (1984)
Glow Plug: Testing and Inspection
Cold Engine
With a normally operating Q.O.S. (Quick On System) with coolant temperature below 140°F and ignition turned to ``On'' position, glow plug indicator
turns on for about 3.5 seconds and No. 1 relay (quick pre-heat) turns on for a few seconds, then off. When ignition switch is turned to ``Start'' position,
glow plug indicator and No. 2 relay (constant heat) will go on and remain on until ignition is returned to ``On'' position.
IGNITION IN ``ON'' (PRE-HEAT) POSITION
Relay No. 1 & Glow Indicator Are Both Inoperative
1.
Starter circuit fuse is burnt out or fusible link wire is open.
2.
Starter wire circuit is open or not properly connected.
3.
Controller is defective or not properly connected.
4.
Starter switch is inoperative.
Relay No. 1 Inoperative
1.
Relay No. 1 is open.
2.
Relay coil in relay No. 1 is open.
3.
Controller to No. 1 relay circuitry is open or not properly connected.
4.
Grounding circuit for No. 1 relay is open or not properly connected.
5.
Controller is inoperative.
6.
Circuit from controller to signal feed wire of sensing resistor is open or not properly connected.
7.
Terminals of sensing resistor are not connected.
8.
Main terminal of No. 1 relay is not connected.
9.
Main contact is open in No. 1 relay.
10.
Terminals in quick preheat circuit are not connected.
11.
Engine harness ground is not properly connected.
12.
Quick preheating wiring is not properly connected or circuit is open.
Glow Indicator Light Inoperative
Light bulb is burnt out.
Relay No. 1 Turns Off Within 2 Seconds
1.
Controller is damaged.
2.
One or more glow plugs are defective.
3.
Wiring at connector is poorly connected.
Relay No. 1 Will Not Turn Off After A Few Seconds
Controller is damaged.
Relay No. 1 Operates When Coolant Temperature Is Above 140°F
1.
Thermostat switch is inoperative.
2.
Circuit has a short.
IGNITION IN ``START'' (CONSTANT HEAT) POSITION
Relay No. 2 & Glow Indicator Inoperative
Starter switch ``R'' circuit is not properly connected or open.
Relay No. 2 Inoperative
1.
Relay No. 2 terminals are not connected.
2.
Circuit between R terminal and No. 2 relay is not properly connected or open.
3.
No. 2 relay coil is open.
Glow Indicator Light Inoperative
Controller is damaged.
