As John Paul diagnoses with this 2011 Volkswagen Golf, there are no coincidences when it comes to diagnosing electrical problems.
Q. I have a 7 year old Volkswagen Golf and it has an odd problem(s). When the car is warm and driven every couple of hours it starts up and runs great. When the car is left overnight, it is hard to start, cranks over for a long time and when it does start it runs rough for a few minutes.
I had an old Chevrolet that did the same thing and it was a bad fuel pump relay. I replaced the fuel pump relay but still the same problem. The odd thing is the dome light doesn’t always work. But here is the curious part, when the dome light works, the car starts up just fine. Any ideas?
A. You actually may have diagnosed your car’s problem.
There is a switch made into the door handle that activates the fuel pump so it can charge the fuel system. This is the same switch that turns on the dome light and activates the alarm. When you open the door the micro switch in the door handle send a signal to the car’s computer then to the fuel pump relay to turn on the fuel pump.
If there is a switch or wiring problem that would certainly cause the extended crank no-start problem. An easy method to check this to put down the window, lock the car, wait a few minutes and open the door from inside, if the alarm doesn’t go off, then I suspect the switch doesn’t recognize the door is being opened.
John Paul is senior manager of public affairs for AAA Northeast. A certified mechanic, Paul tests dozens of new cars each year and also hosts a radio show on AM 950 wrolradio.com