By Phil Arendt
Faulty Clutch Hinders A/C
Question 1The air conditioner in my Dodge Sprinter 2500 truck is not working properly. When stopped at a light the temperature of the air blowing from the vents warms up quite a bit. While driving the air temperature drops and feels normal. Obviously, with winter approaching repairing this issue is not a top priority but I’d like to get it fixed.
I went to a repair shop
where they replaced the air compressor, drier, flushed the system and
recharged. This did not fix the
trouble.
When I returned they
replaced a sensor or switch on the drier.
They said it controlled a fan at the condenser, but this has not fixed
the trouble. Now they don’t know what is
causing the issue.
I use my truck for
work. It has a 2.7 diesel engine. I take great care of it. It’s in great condition. It has nearly 200,000 miles. I plan to drive it another 100,000
miles. Do you have any suggestions?
T.M., email
Answer 1
Another 100,000 miles is not
out of the question, but you need an air conditioner that works as designed. During the winter months the system defogs
the windows when setting defog on the controls.
You have spent a lot of cash
in an attempt to repair the trouble. Ask
your favorite technician to consider the trouble might be caused by a failed
engine cooling fan clutch.
In addition to an electric
fan at the air conditioning condenser there is a thermal/mechanically driven
fan at the front of the engine that draws air through the a/c condenser and
radiator. If the clutch on the fan is
not engaging as designed air flow that is necessary to cool the air
conditioning condenser, radiator and engine coolant is impaired especially when
the vehicle is stopped. Replacing the
fan clutch just might be a lasting repair.
It’s Time For An Overhaul
Question 2When the transmission in my 1999 Honda Accord with a 6-cylinder engine shifts from first to second gear it takes a long time to shift and when it does the engine revs up before it connects second gear.
I went to a repair shop
where they did some tests and drove the car.
Tests did not find any trouble codes.
They also checked a speed sensor and it was fine too. They say the transmission needs an overhaul
or replacement.
The car has 155,000
miles. It’s in excellent shape. I’ve owned it since it was new and have
followed the factory maintenance schedule.
I don’t want to part with it and buy a new one. Is there anything else that could cause this
trouble? D.L., email
Answer 2
Since you have taken good
care of the vehicle there is no reason to buy another. Certainly a transmission overhaul or
replacement costs much less than a new car.
It appears your shop has
made a sound diagnosis. It’s likely the
transmission needs an overhaul. Just in
case, since this is an expensive repair consider going to another shop for a
second opinion.
Flickering Lights Due To Faulty Alternator
Question 3
I just read your column concerning a problem encountered by K.J. with flickering lights. I had the same problem in my car. It ended up being a defective voltage regulator in a newly installed aftermarket alternator. Once the defective alternator was replaced the problem was resolved. Can you forward this information to K.J? S.F., St. Paul, Minn.
Answer 3
Hopefully K.J. is reading
today’s column. Certainly a faulty
voltage regulator may cause lights to flicker.
After all if a nice steady stream of electrical power is not being
supplied the lights pulse with changes in electrical output.
As vehicles gain more and
more gadgets with each passing model year the demand on the alternator is increasing
so much so that engineers are in the process of doing away with the 12 volt
system that has been the standard for about 60 years to a 24 volt or higher
system to accommodate all the fun accessories and safety related systems we
enjoy.
Test Fuses
Question 4Recently, the speedometer quit working in my 1995 Ford F-250 Eddie Bauer pickup. It has a 7.3 – liter diesel engine. Since I do a lot of repairs myself I ordered a replacement and installed it. Unfortunately, after replacing the part the speedometer and odometer do not work and now the transmission is not shifting properly. I checked the wiring to the speedometer and transmission but everything looks fine. I did a continuity test on as much of the wiring as I could and did not find any open circuits. The plugs and terminals look fine. I also checked the vehicle speed sensor. It tested fine but I replaced it anyway.
The check engine light is
not on. Tests at a shop did not find any
trouble codes. Now I’m stuck. Do you have any suggestions? T.D., email
Answer 4
Sometimes we make mountains
out of molehills. In my years I have learned
that staying calm and reverting to the basics often leads to finding the cause
of perplexing troubles. In your case,
consider checking fuses. Sometimes in
the process of replacing parts we forget to disconnect the battery negative
cable. It’s the first step to
repair. When we forget this step it’s
entirely possible to blow a fuse or two.
Test the fuses. I’ll wager that in the process of
disassembling the dash a plug touched a ground and wham a fuse blew to protect
the circuit. In hast it has happened to
me and it might be the cause of these troubles.
Shaky Engine Caused By
Frosty Throttle Body
Question 5Winter is coming and I need to have an issue repaired before temperatures fall below freezing.
When it’s cold the idle in
my 2000 Saturn LS2 becomes rough and it lacks power. The 3.0 engine starts fine but vibrates until
it warms up. Sometimes the check engine
light turns on and then goes off after I have driven a mile or two. Also, the throttle sticks at times.
Last winter when this
happened, a shop cleaned the throttle body and reset a computer. A week later the trouble returned but the
weather warmed up and I have not experienced the trouble all summer.
My car has 144,000
miles. It’s in like new condition. Can you help before cold weather sets
in? R.T., email
Answer 5
An intermittent problem for
a technician and car owner can be a nightmare.
Fortunately in your case there might be a solution. When the weather is cold some SL2s develop
frost in the throttle body. Ask your
technician to consider this as a possible cause.
In some cases reprogramming
the engine control module cures the trouble.
At other times replacing the throttle body is a lasting cure.
What will cure the condition
all depends upon technician findings.
Trunk Fails To Pop Open
Question 6Okay, here’s my problem. The power trunk release does not work in my 2009 Toyota Avalon. I bought the car this summer and was aware that it did not work. Since then I have been tinkering to restore the convenience. I have replaced the dash switch and motor on the trunk.
When I first looked into the
problem I checked for blown fuses. They
were fine. I also found electrical power
at one of the wires connected to the motor.
I replaced the motor thinking it was defective. When that did not solve the issue I replaced
the dash switch.
I’ve had this option in
every car I have ever owned and miss it.
What do you suggest I do next?
N.P.B., email
Answer 6
You don’t know how much you
miss an accessory when it does not work.
Without proper test
equipment you are at a disadvantage but don’t despair. When the dash switch is depressed a signal is
sent to the body control module. The
module then grounds a circuit to activate the motor to unlatch the trunk. It’s possible there is an open ground wire
somewhere along the path to the trunk.
Also, there could be an issue with the valet switch in the glove
compartment. Additionally, it’s possible
the body control module has a fault.
Check the switch in the
glove compartment. Also check for an
open circuit between the dash switch, valet switch and control module. Repair might be as simple as tightening a
terminal within a plug. If the circuits are functioning as designed, consider the trouble is in the control module. If so, it’s time to ship troubleshooting to your favorite shop. Specialized equipment is needed to communicate with the module to determine if indeed it has a fault. Also, the test equipment checks the integrity of the circuit.
Thank you for all the great
questions. Dr. Gizmo can’t wait to
answer more.
Phil Arendt is a columnist, consultant and A.S.E.-Certified
Master Technician. Readers may send
questions to Dr. Gizmo at P.O. Box 548, Cary, IL. 60013 or e-mail address mailto:drgizmo@hotmail.com. 10/21/2013 ® DR. GIZMO © 1989 - Present
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