Vehicle Related Conditions

After the battery has been charged or tested and has proven to be a good battery, the cause of the no-start or slow cranking condition must be determined to prevent comebacks. If no obvious cause is evident, the vehicles electrical system should be diagnosed using the following steps:
^ If the battery has passed a load test and the engine still will not turn over or is difficult to start, check the starting system. Refer to Starting System Check. Initial Inspection and Diagnostic Overview
^ If the starting system inspection reveals no abnormal conditions, but excessive cranking is required to start the vehicle, the cause must be diagnosed and corrected to reduce battery demands. Two possible causes for excessively long cranks are ignition system or fuel problems.
^ If the battery discharges while the vehicle sits for a few hours or days, the vehicle should be diagnosed for parasitic loads. Simple connection of an ammeter in series with the battery may not find the cause as the condition may not show up when power is restored unless that particular component is repeatedly cycled. Refer to Battery (Parasitic) Load Test. Battery (Parasitic) Load Test
^ If a battery becomes discharged and no excessive current drain is found, the operation of the charging system should be checked. Refer to Charging System Check. Preliminary Information - Charging System