Brad, we have a 2005 Ford Focus station wagon. About two years ago,
some of the warning lights would flash on and off for a fraction of
a second, about every two weeks or so. It then started doing it to
all of the warning lights. Then one day we went into a food store,
on the way there everything was normal. When we came out, the door
would not unlock, had to use the key. Everything was dead, and the
car would not even turn over. I checked the battery connections;
they were clean and tight. I then figured I had an open circuit in
the battery. I called AAA and was told that it would take about an
hour for someone to come. After about 40 minutes, the radio started
to play and the car started like normal. I got a new battery, and
after a few months it started to act up again. The engine would cut
out for a second or so every now and then, and warning lights would
flash on and off.
I took it to a
dealer, and it was normal driving there. They could not find
anything wrong, except a ground that had a little corrosion on it.
There were no faults on the computer, so they flashed the computer
anyway. It was OK for several months.
Then on Oct.
22 when I was going to get gas, it started again. The engine would
cut out for a fraction of a second, warning lights would flash, and
the radio stations would change. I filled up the tank and got in the
car, and everything was completely dead. I checked the battery
connections, and they were all OK. I got back in the car and
everything was normal.
I took the car
to the Ford dealer. Again they checked it out, drove it around,
checked the computer, no faults. Since they could not see the
problem, they could not correct it. What could cause this?
Daniel, your situation has to be very frustrating, but it does
differ from Linda’s Lucerne problem last week, as you can play
detective to a much greater degree. Your Focus clearly has an
intermittent open/high resistance electrical fault near the trunk of
the tree — battery, terminal connections, cables, and battery
junction box. You can aid the diagnostic process or possibly solve
the issue yourself with some simple tests. Start by obtaining an
inexpensive digital multimeter, such as Sears Craftsman DMM model
MN16A, which you can find for less than $30. Next, be sure both
battery terminals and battery posts are shiny-clean and tight.
Next time the
Focus acts up, immediately check for available voltage of about 12.6
volts across the battery terminals. I’m guessing this will be good
— if not, it’s a second devil-battery. Then touch any of the
fuses within the battery junction box, in the left rear corner of
engine compartment, with the red lead. Your black meter lead is
connected to the negative battery terminal. Again, check for
available voltage. If this test fails, the fault is between the
battery’s positive terminal and the junction box. I
If this tests
OK, turn on the headlights and touch the red meter lead to the
battery negative terminal post, and the black lead to shiny engine
metal. If the meter reads a value that’s not very close to zero,
the ground connection between the battery and powertrain/body is
can also be tried when the car is behaving, as you wiggle cables and
connections — look closely for an abrupt downward or upward change
in the meter readings. This will be easy to fix, once the
measurements suggest the path.