97 Cabrio No start, No turn over when hot?

Question

I have a 97 VW Cabrio that will not even crank over when it is hot outside. It starts from my garage and then will not start after it sits in the sun. I have replaced the Battery & Starter and still have the same problem.

Answer 1

Starter (and solenoid?) Did you also look at the ignition switch?   Sun gremlins.

Answer 2

  You have several possibilities here, but you'd need to start with the basics.  Firstly, even if the battery is "new", you need to load test it to determine if its actually good or not.  Secondly, you'll need to check the starter for amp draw and voltage.  Assuming that these items pass, then check for voltage loss thru the battery cables, you should have no more than .5 volt loss at the starter at maximum, and check for ground circuit issues.  Most likely assuming that the starter and battery do check out, is that you have a excessive voltage drop out caused by either battery cable or ground circuit fault.  Another possibility is a mechanical fault with the motor, but that's not likely.  Does the vehicle compression start when hot?

Hope this helps, a car nut.