Suburban 3/4 Ton 4WD V8-305 5.0L (1986)
If a solder joint problem results in a "hard" failure, normal test procedures will usually pinpoint a faulty control module. Many symptoms caused by poor
solder joints in the control module result in intermittent problems, but they may be hard to duplicate during troubleshooting. Control module's with
solder joint problems are sensitive to heat and vibration. You can check for these internal control module problems in either, or both, of the following
ways:
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Remove the control module from its mounting bracket and extend it on the harness so that you can expose it to the vehicle heater ducts.
Alternatively, use flexible ducting to route air from the heater to the control module location. Then run the engine and operate the heater at
the "MAX HEAT" position. This exposes the control module to approximately 140°F.
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With the engine running, tap on the control module several times with your hand or finger tips to simulate vehicle vibration.
If the engine stumbles or stalls, the "CHECK ENGINE" "SERVICE ENGINE SOON" or "MALFUNCTION INDICATOR" light flashes, or any of the
previous symptoms occur, the control module may have bad solder joints on the circuit board.
