Tuesday, August 08, 2006

1994 Grand Prix: wires shorted but no codes!


Car fuel pump was changed 2 weeks ago but won't start. Every time the starter switch is turned on, the fuse at the electrical center #2 inside the hood blows. The fuel pump circuit does not seem related to this job. There is no check engine light code when scanned. What to do?

Basic Concept:

A good way to trace a shorted wiring is thru the use of a WIRING DIAGRAM. Looking at it, there seems to be no connection between this problem and the fuel pump. If it is, it should have acted up as soon as the fuel pump was installed.

Repair Strategies:

Using a wiring diagram, connect a jumper wire hooked up to a circuit breaker to allow the circuit to work continuosly. When the amperage goes high and trip the breaker, it will just reset itself. You can also use a needle counter gage to monitor the location of the short. Once this system is set up, you can start disconnecting the circuit loads:

theft deterrent relay
trany range sensor
starter assembly

Disconnect these loads one at a time until the breaker stops tripping. The last load you touched is the location of the shorted circuit.


The needle counter gage has a needle that oscillates in the direction of the short. For more details, check ATS.


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