Professional_Tool_And_Equipment_News_February_2020 - 27

FLIR TG275 or the Launch Tech USA
Thermal Imager. When electrical current is flowing, it generates heat. Using
a thermal camera on the fuse panel will
indicate which circuit is generating heat.
In the case of the Acura, our initial
tests found no issues with the connections, battery, or charging system, and
just as importantly, no current draw.
Taking into account that the vehicle's
owner stated this problem usually
surfaced after driving on a warm day,
we thought about what systems might
be active under those conditions. The
first two things that came to mind
were the cooling fan and the air conditioning system.
p This image from Mitchell 1 shows the
various components powered on the same
circuit as the handsfree link.

with the customer to find out the conditions in which the vehicle is operated
when the problem arises.
Our customer stated the vehicle
would occasionally not start, but a jump
start would allow the vehicle to run all
day long. The issue seemed to occur
more often after driving on a warm
day, rather than night driving. Our first
test is always a scan of the vehicle to see
if there are any codes recorded. You
should check every module but pay special attention to any communication (U)
codes. Checking for codes in all modules will allow you to determine if there
are any issues with the security system
that could be the cause of a no-start.
Next would be a visual inspection of
the battery and charging system connections. In order to fully inspect battery
connections, you should remove the battery cables to make sure there is no corrosion between each cable end and the
battery. If there is no corrosion and the
connections seem secure, use a battery
tester, such as the Associated Equipment
Intellamatic Smart Battery Charger and
Analyzer, to load test the battery.
If the battery passes the load test,
re-connect the battery cables, start the

vehicle, and test the charging system
using the proper test outlined by the
vehicle manufacturer. Keep in mind,
a charging system combined with
a scan tool may be necessary to test
some vehicles.
Once the battery, connections, and
charging system have been tested and
ruled out, it is time to check for a battery drain. There are many ways to
check for a draw, but one of the easiest is to connect a digital multimeter
(DMM) between the battery and the
negative cable end.
A good way to make sure you do not
damage your DMM's internal fuse is to
build a wire clamp with a built-in 5A
ATC type fuse that you will connect
between your DMM and the battery. If
there is a high current draw, the ATC
fuse will blow and protect the internal
fuse. This little modification can save
you a few dollars for the fuse, but more
importantly, a lot of time by not having to run around trying to locate the
internal fuse for your DMM.
If you detect a battery drain of
any significance (over the allowable
amount listed in your vehicle information source) you will need to locate
the source of the drain. The fastest
and easiest tool I have found to do this
is a thermal imaging camera, like the

www.VehicleServicePros.com

FEBRUARY 2020

ISOLATE THE ISSUE,
REPAIR THE VEHICLE,
AND VALIDATE
THE REPAIR

We had one of our drivers take the vehicle on a long test drive while using the
A/C. When he returned from the drive,
we parked the car in a shady place and
shut it down. After about an hour we
used the thermal imaging camera on
the fuse panel again. This time, the A/C
compressor relay showed a heat trace.
We removed the fuse and used the Fuse
Buddy from Electronic Specialties to test
the circuit. The Fuse Buddy has a connector that replaces a fuse, and a digital
display that shows how much current is
flowing through the circuit.
Our Acura showed about 1.5A flowing through the A/C circuit with the
engine off. We then disconnected the
relay, and the flow of current stopped.
We then switched the A/C relay with
the horn relay and the current flow
remained at 0A, indicating that the
original A/C relay was faulty.
Since many times a relay failure can
be caused by excessive resistance in
the circuit, we felt it prudent to use our
DMM to make sure the A/C compressor
clutch did not have too much resistance.
Our test did not show any faults in the
system. Also, to make sure there was
not a system overcharge that could

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