"Dr. Gizmo"
By Phil Arendt
Interior Lights Shine When
They Shouldn’t
Question 1I own a 2001 Chrysler 300M. The problem is intermittently the interior lights turn on while driving or when it is parked. I had my dealer look into the trouble but they did not fix the problem.
The battery took a beating
from being discharged so I had it replaced.
I also checked for recalls without success. Can you help?
M.K., McHenry, IL
Answer 1
It’s time to buy a new
car. All kidding aside the trouble
likely is caused by a faulty door switch but it’s possible a control module is
at fault. If the car has been in a
collision a technician needs to know about the repairs. This clue will help find the trouble as even
a poor adjustment in door alignment or door latch can cause this
condition.
Additionally, it’s possible
a door latch needs tender loving care.
Lubricating the locks and latch assemblies could cure the trouble.
Right Turns Cause Clicking
Noise
Question 2I have a 1999 Oldsmobile 88 with 90,000 miles. When making right turns I hear a clicking sound in the right front area. The wheel bearing and axle on the right wheel have been replaced. Also, the wheels have been aligned. Is it possible the strut is causing the noise? G.P., Algonquin, IL
Answer 2
Make only left turns and the
trouble is resolved. I’m sorry I could not
restrain myself. The noise in your car
could be caused by a failing upper strut bearing. It is not likely the strut itself is making
noise. It’s also possible the right
constant velocity joint on the right axle is excessively worn and clicking. The joint and axle are separate parts.
When you have a minute, with
the vehicle stationary turn the wheels left and right. If the upper strut bearing is causing the
noise you might hear the sound. If the
noise only occurs when the car is moving more than likely a rotating part such
as a constant velocity joint is the source of the sound.
Air Bags No Longer Work
Question 3The air bag light in my 2005 Buick LeSabre turns on and stays on. Can you tell me what is wrong? P., email
Answer 3
There are many causes for
the air bag light to illuminate including failed sensors, modules or even
failed circuits. The fact that the
warning light stays on is a blessing.
This indicates that the trouble is constant. A technician will have a much better chance
of determining the cause of the issue than if the light was turning on once in
a while.
Consider taking the vehicle
to your favorite repair shop. Tests will
find the cause. A common problem that
causes this issue is a broken clock spring under the steering wheel. If so, repair will be a snap.
In the meantime be aware the
air bags will not deploy in a collision so have the system repaired as quickly
as possible.
Question 4
I have a 2003 Chevrolet Tahoe with 154,000 miles. Except for the poor gas mileage, I really love the vehicle. My question refers to the yellow security light on the instrument panel. It stays on all the time the truck is running. I've checked the fuses and don't find any blown.
I bought the truck new and
this problem began after I had a wire repaired in the steering column. Do
you have any idea why this would stay on and how I can correct the problem,
short of putting a piece of black tape over the light? E.F.K., email
Answer 4
Duct tape comes in so many
colors, patterns and styles you might find it useful to cover the light and
it’s much more attractive than black electrical tape. All kidding aside, it’s possible the wiring
to the antitheft system in the steering column was damaged during repairs. It’s also possible the antitheft system needs
reprogramming. Additionally, there may
be a problem in the ignition key.
Consider revisiting the
repair shop that repaired the column wiring to address the issue. Tests should find the cause. If this condition is caused by a misstep, you
should not have to pay for repairs.
Time to Troubleshoot Circuit
Question 5I have a 2005 GMC Safari with a 4.3-liter engine and 160,000 miles. I’m having trouble with engine starts. A friend who has a lot of knowledge about GMCs replaced the fuel pump. After this the trouble continued so he did more testing and found a communication problem with the engine module. He installed a new module and programmed it but the trouble is not fixed. Now during tests one time his meter reads 12 volts at a wire and at other times the same wire reads 1.2 volts. He says this is causing the problems. He thinks the new control module might be the cause but he is not sure and the place where I bought the module won’t take it back unless my friend is sure it is defective.
Do you think the module is
bad or is something else causing the trouble?
R.R., email
Answer 5
Today, most vehicle problems
are caused by an electrical issue. And
certainly it is possible the recently installed powertrain control module might
be defective. Since your auto supply
store will not take it back until it is proven defective, your buddy should
consider troubleshooting the wire with variable voltage readings. It might have a small break or it might be
damaged due to chaffing against another part.
Perhaps there is a plug in the circuit where a pin terminal is corroded
but your description of the trouble lends to a loose terminal. He should check for looseness and
corrosion.
If a process of elimination
proves there is nothing wrong in the circuit he can say with a reasonable
degree of certainty that the PCM is defective when he returns to the auto
supply store.
Tires Create Heat That Boils
Oil
Question 6I have a Ford Explorer with a 4.6-liter engine and a differential in the front for four-wheel-drive that gets so hot it can’t be touched. Also, once it gets hot oil comes out all over the bottom of the vehicle.
I took it to a repair shop
where a mechanic filled the differential with oil. We went for a drive and by the time we
returned to the shop oil was dripping and it was so hot the oil was smoking on
the differential. We only drove about
six miles. My mechanic could not find any
leaks. The four-wheel-drive worked fine
but after looking at the vehicle for a while he came to the waiting room to say
that I had the wrong size tires. He said
that the tires in front are not the same size as the rear and none of them are
of the proper size for the vehicle. I
purchased the custom set of tires online.
I had them installed but the shop that did the work never mentioned that
they would cause a problem.
Does this seem right to
you? K.J., email
Answer 6
Tire size is a critical
aspect in the ride and control of a vehicle and even more critical with
four-wheel-drive. It can also adversely
affect the performance of the antilock brake, stability control, traction
control and all-wheel-drive systems. Not
only can these systems be impaired but engine and transmission operation can be
affected due to wheel speed sensor and other computer sensor inputs such as
transmission and engine speed to manage fuel deliver, transmission shift points
and more while driving.
More than likely your
vehicle is suffering from differences in rotational speed caused by tires of
different sizes. This causes great
stress on the differentials in the front and rear and the transfer gear box
that connects the transmission and engine to the front and rear
differentials. This can cause huge torque
differences and heat. Obviously the heat
built up in your front differential is high enough to cause oil to vaporize
into smoke. And that’s on the outside of
the unit. The temperature of the gears
inside must be higher resulting in heat high enough to boil oil right off
the rotating parts. Continued operation
with these tires and conditions will soon cause the differential and maybe more
to fail.
I suspect your technician
suggests that you consider installing tires of the size originally intended for
the vehicle suggested by the carmaker. Take
his advice.
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. 09/30/2013 ® DR. GIZMO © 1989 - Present
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