Nissan Repair: ticking noise under dash of 1986 300ZX, door locks, ken ken

Question
  All of a sudden I can hear a rather pronounced (not that loud) ticking noise under the dash on the driver's side. It sounds similar to the directional light sound, but it clearly is not the directional light. The ticking sound is constant during the whole time the car is running and is not any louded or softer whether the car is moving or in neutral. My mechanic thinks it is in the solenoid "bar" (a string of six solenoids) that he pointed out to me under the dash, but he is not sure and feels that it would be expensive to fix possibly because it would take a lot of time figuring out what is causing the noise. Thus far it is just a bothersome sound since it has not effected the operation of the car. Thanks for your help.

Ken  

Answer
Ken,

It is a relay or a circuit breaker that is overheating.  When the circuit gets hot the thing opens up and then when it cools it closes.  I would get a stethoscope for the parts store that you can use to isolate it and then replace it.  Now, I once worked on a 240SX that was doing it and it turned out to be a wire that was grounded under the drivers seat.  Well, it was a direct short and it was not the circuit breaker but the grounded wire that was causing it.  The mechanic knows that electrical is a pain to trace so you could do it yourself and save a bundle.  First, find which circuit breaker is making the noise and then look up what it protects and then check out each system.  In the case of the 240SX it was the converter under the car that got so hot it melted the insulation off the wire.  Yours could be as easy as an accessory like the door locks or something you might not use too often.  Check it out and email me back.