MACS Service Reports - 2016 - SEP8

AND ONE MORE - ON A KIA
When we review this case, we suspect that if you just read
the previous one (Hyundai Tiberon), there will be some familiar
sounding aspects. And we don't just mean that Kia is a sister
company to Hyundai and that this car - a 2004 Spectra - also
has a 2.0-liter engine. In fact, the issue is actually the reverse of
what happened with the Honda CR-V that we discussed earlier
in this article.
The car came in for no A/C and compressor noise. The compressor was replaced and on the dealer's recommendation, an
evaporator temperature sensor also was installed. The system
operates but cuts out (compressor disengages) when the engine
is warm, but cuts out at idle. It comes on again when engine
rpm reaches about 1500 and continues to operate when the car

is operated at medium road speeds. Sounds like a throttle position sensor, or maybe an engine rpm signal, or perhaps even the
rpm sensor on some compressors. What about low refrigerant
charge? But no.
The answer once more is low coolant, in fact about a couple of
quarts low. When the system is topped up, the flow of coolant
at normal operating temperature flows over the sensor, in this
case cooling it and restoring A/C operation. So the bottom line
is: a properly functioning engine cooling system is an important
contributor to the proper operation of the A/C too. You know
about the need for a correctly-functioning cooling fan system,
and we hope we've made the point about coolant too. ■

"HAS TO BE A BAD CONNECTION, RIGHT?" WELL MAYBE NOT
none, which could lead to replacement of the rear blower speed
control module. After all, those speed control modules are such
a common failure item and FCA (Chrysler) has had its share.
If that module is replaced (Fig. 9), it's sure to be a permanent
replacement, but it won't help.
It's a lot faster to start by checking the service bulletins, where
you'll find one for a reflash to correct this condition on 2012-2103
models. We don't have access to the FCA software, but apparently there was some corruption in the signaling from the underdash HVAC module to the rear system module.
Shops without a J2534 Pass-Thru device are, sadly, too
likely to start diagnostics by looking for a physical problem
they know they can correct. That not only often leads down
a dead end, but to unnecessarily replaced parts and a lot of
wasted time. If you still
can't justify reflashing - and yes there
are shops that don't
see enough volume to
make the investments
in time and equipment
- at least make the correct diagnosis. Then
farm out the job to a
dealer or another inFigure 9: This electronic blower control
dependent shop, take
module in the rear HVAC of the 2012-13
your
professional
Dodge Durango is No. 1 on the suspect
list when the rear passenger can't change
discount and satisfy
blower speeds. But a new module will do
the customer at lowno good. The fix is a reflash of the system.
er cost. ■

techauthority.com (Fiat Chrysler)

Although we long have said, "Start any diagnosis with a check
for a service bulletin," technicians typically will use what they
consider a common sense approach that often leads them to dig
right into the car. Here's an interesting example from a 3-4 year
old Dodge Durango with front dual zone Automatic Temperature Control and rear HVAC. The vehicle comes in with the complaint "No Rear Blower." Or more precisely, the blower motor
won't respond to the rear passenger using the rear HVAC control panel (enabled at the front HVAC controls) to change blower
speeds. The shop confirms the complaint and goes to the wiring
diagram, making the logical assumption that a wire must have
come unplugged or somehow been damaged, for after all, the
rear blower DID work until it just didn't.
The circuit is pretty straightforward, and available in online
service information, so we won't reprint it here. There's the rear
blower motor and rear blower power module (which can provide infinitely variable speed signals to the motor) in the rear
HVAC housing, which is behind the rear quarter trim panel on
the passenger's side (Fig. 9). That rear blower module is powered from a blower relay in the power distributor center, which
itself carries a dedicated power feed from a fused circuit in the
TIPM (Totally Integrated Power Module). The rear HVAC control module is wired to the main HVAC control module under
the dash.
The factory-recommended diagnostic approach is with a scan
tool (if you have one with the OE software), but we'll tell you
there are no trouble codes. It would seem reasonable to check
for power to the blower motor, which would require removing
trim for access. But before you think the technician should go
further to do what will not be quick work, we'll add that there is
MACS Service Reports is published monthly by the Mobile Air Conditioning Society Worldwide. It is distributed to members of MACS Worldwide
and is intended for the educational use of members of the automotive air
conditioning service and repair industry. Suggestions for articles will be
considered for publication, however, MACS Worldwide reserves the right
to choose and edit all submissions.

Editors:
Elvis Hoffpauir, Steve Schaeber
Production Designer:
Laina Forcey
Manager of Service Training:
Steve Schaeber
Mobile Air Conditioning Society Worldwide
P.O. Box 88, Lansdale, PA 19446
Phone: (215) 631-7020 * Fax: (215) 631-7017
Email: membership@macsw.org * Website: www.macsw.org

Unless otherwise noted, all photos/art by author.

September 2016

MACS Service Reports

http://www.techauthority.com http://www.macsw.org

Table of Contents for the Digital Edition of MACS Service Reports - 2016