Dear Tom and Ray: I need your help in solving a problem that really has me stumped. My 1992 Nissan Sentra has a few strange habits, most of which I can live with - but not this one: When the car sits in the sun with the windows closed, it just will not start. I turn the key and get absolutely nothing. If I open the window and wait about five minutes, it starts up just fine. I replaced the battery, the starter and the battery cables. Nothing worked. Then I took it to a shop, and the mechanic wanted to replace the battery, the starter and the battery cables.It started fine all winter. - Erik
Tom: You gave us two excellent hints, Erik. Now, wouldn't it be impressive if we could actually put them to some intelligent use?
Ray: It would, wouldn't it? Well, one hint is that it's related to high temperatures inside the passenger compartment. So that would limit it to parts located where, Tommy?
Tom: Inside the passenger compartment!
Ray: Very good. And the second hint is that absolutely nothing happens when Erik turns the key. And that means it's got to be a part that can completely interrupt current to the starter, because otherwise you'd get at least some sound or hear some effort by the car to start.
Tom: So my guess is that it's a bad ignition switch.
Ray: Good guess, but probably wrong. My guess is a bad clutch interlock.
Tom: It's an easy thing to test, Erik. Have your mechanic remove the clutch interlock and just shunt those two wires together - taking the interlock completely out of the circuit. If the problem goes away, have him install a new clutch interlock (it's cheap), and you'll be all set.