Saab: saab not starting, neutral safety switch, battery cables

Question
QUESTION: We have a Saab 9-5, 2001 model with about 95k miles.  The car will, and it seems random, not start.  Sometimes it is hours after the car has been off and at other times, it is right after the car has stopped.  When you turn the key there is no sound coming from the engine at all.  All the dash lights come on and things appear normal.  I've looked at the battery cables and they appear to be clean as does the ground to the body.  Recently the engine light came on, but it is sporadic as well and may have been caused by not tightening the gas cap after a refill.  Any thoughts...

ANSWER: Gregg:
  With no sound whatsoever coming when you put the key in the start position, the problem can be in three places, listed below in order of likelihood:

1. The starter itself; would need replacement.

2. The neutral safety switch (only on automatic transmission equipped vehicles); likewise replacement required.

3. The key switch itself; requiring disassembly of console and replacement of switch.
A typical mechanic should be able to identify which of these is at fault in just a few minutes. OR, if you are handy and have a voltmeter, you could as well.

         Hope this helps,
         Jerry

---------- FOLLOW-UP ----------

QUESTION: I have a volt meter - what would I have to check to narrow down the options.

By the way - thanks for your input.

Gregg

Answer
Gregg:
 First, you'll need to physically locate the starter motor. Once located, you'll note 2 wires going to it, a large and a small one. The large one comes directly from the battery and provides the main current.The small one is a 12 volt signal that originated from the keyswitch when in 'start' position. So, with the voltmeter connected between the small wire and ground,AND the keyswitch in start position, you should consistently get 12 V. If you do, then the starter is faulty. If you do not, then you must go progressively 'back' to the signal source. The key word is "consistently". With problems like this, intermittency can make troubleshooting difficult since the problem never appears when you "want" it. If there is no voltage as in the above step,
and if your vehicle is an automatic, then you must do a similar test at the neutral start switch. This is located on the transaxle housing with 2 wires going to it. It prevents the starter motor from being energized except when the gear lever is in either "park" or "neutral". Likewise check for 12 V on both sides of this switch when in the start position AND the gear lever is in either "P" or "N".
Finally, a similar test must be done if still no voltage, back at the key switch.
         Good luck!

         Jerry