Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Glow Plug Control - Failures/Intermittent Problems
1985 Buick LeSabre V8-350 5.7L DSLSECTION Glow Plug Control - Failures/Intermittent Problems
Bulletin 86-6-19
Date June, '86
Ref. No. 86-133-6
SUBJECT: DIESEL GLOW PLUG CONTROL FAILURES
MODELS AFFECTED: 1984-85 MODELS WITH 4.3L OR 5.7L ENGINES
1984-85 model diesels use a control module that contains a timer module and a relay. There have been cases where control module malfunctions were the result of an open circuit in the unit. This is particularly true of intermittent problems with the glow plug system. To correct this condition, remove the glow plug module from the car and remove the cover and the timer module as shown in illustration.
Visually examine the timer module for any evidence of damaged components or circuits. If no problems are noted, proceed as follows:
Pull the relay wires out of both clips. Scrape the end of the wires to remove the coating. Supply a ground to one end of the relay wire and then momentarily place 12 volts to the other end to make sure the relay works. (The sound and motion of the relay working is very evident.) If the relay works, position the scraped end of the wires down into the clip area as shown in View A of illustration, and install the timer module. Solder the prongs of the timer module to the clips and the wire. Reinstall the cover and reinstall the unit on the car.
Place a test light across the relay terminals, turn on ignition key and check system operation. Make sure the wait light operates satisfactorily and the test light goes out after the engine has been started.
WARRANTY INFORMATION
Add .1 hour to the published time to solder coil wires.
Date June, '86
Ref. No. 86-133-6
SUBJECT: DIESEL GLOW PLUG CONTROL FAILURES
MODELS AFFECTED: 1984-85 MODELS WITH 4.3L OR 5.7L ENGINES
GLOW PLUG TIMING MODULE:
1984-85 model diesels use a control module that contains a timer module and a relay. There have been cases where control module malfunctions were the result of an open circuit in the unit. This is particularly true of intermittent problems with the glow plug system. To correct this condition, remove the glow plug module from the car and remove the cover and the timer module as shown in illustration.
Visually examine the timer module for any evidence of damaged components or circuits. If no problems are noted, proceed as follows:
Pull the relay wires out of both clips. Scrape the end of the wires to remove the coating. Supply a ground to one end of the relay wire and then momentarily place 12 volts to the other end to make sure the relay works. (The sound and motion of the relay working is very evident.) If the relay works, position the scraped end of the wires down into the clip area as shown in View A of illustration, and install the timer module. Solder the prongs of the timer module to the clips and the wire. Reinstall the cover and reinstall the unit on the car.
Place a test light across the relay terminals, turn on ignition key and check system operation. Make sure the wait light operates satisfactorily and the test light goes out after the engine has been started.
WARRANTY INFORMATION
Add .1 hour to the published time to solder coil wires.
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.