Expert: Roland Finston - 10/25/2011

Question
QUESTION: would the full pump make s fast ticking sound on a 01 Chrysler LHS

ANSWER: If it sounds like it is coming from the fuel tank, yes. But it should only sound for about a second unless you then try the starter. Relays in the box under the hood will also do clicking when the voltage is being dragged down on the battery due to a low battery charge or a short. And they will go on for much more than a second. So tell me where the sound is coming from.

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QUESTION: The sound is coming from behind the engine.it is comming from the back side of the engine.

Answer
Hi Richard,
I don't know of any relay in that location. The fuel pump is in the rear, in the tank, so I doubt that is the source because the circuit is set up that if the engine isn't running then the fuel pump won't run either. Does the starter motor work?
If you mean by chance that it clicks only when you are trying the 'starter' position of the ignition key, then I would believe that the battery is too weak to actually drive the starter motor and what you are then hearing is the starter solenoid switch which would be at the rear end of the engine at the place where the engine joins to the transmission.
When there is either a weak battery or a short circuit that drags down the voltage on the battery that solenoid switch will click on-off-on etc. when you try to activate the starter motor.
However if the clicking is present when you just simply turn the key to the 'run' position of the ignition switch I can't identify what would be clicking from behind the engine as there are no other electrical switches in that region that I can imagine. If you can ID exactly what is clicking and tell me if it clicks when you turn the key to 'run' or only when you turn the key to 'start' I would be better able to help.
If this began with the engine shutting down while you were driving and there was no illumination of the battery warning light then I suspect that some wire shorted out the battery current and it is still doing so. But where that is has to be determined.
Roland