Q: The red brake
warning light on my 2005 Ford F-150 comes on at various times. Can
you suggest what I might do to check for the cause?
A: According to my
ALLDATA wiring diagrams, your F-150 has three possible or intended
causes for the red brake indicator to illuminate.
First is the bulb
check process when you roll the key to the crank position as you
start the engine. This proves the light bulb works.
Once the truck is
running, the other two possible causes are the parking brake switch
and the master cylinder reservoir low fluid level switch. A grounded
wire leading to either switch is a distant fourth possibility.
Letís start by
checking the master cylinder fluid level. If it is low, filling it
should do the trick to extinguish the light. Use only fresh DOT 3
brake fluid from a sealed container. A low reservoir is cause for
further investigation. It would be prudent to check brake lines,
hoses, calipers and master cylinder for leakage. Itís also
possible the fluid level is low due to extended caliper piston
positions as a result of worn or thin brake pads. This is the more
If the fluid level
looks OK, weíll next look for a faulty low fluid warning switch.
It sounds like the light is intermittent so youíll need to wait
until the next time it comes on to do the following: With key on and
engine off, unplug the master cylinder fluid reservoirís
3-terminal connector. If the light goes out, there is something
wrong with the fluid level float switch.
The parking brake
switch is next. Itís a bit more difficult to get to, as it is
located on the foot pedal mechanism. Try this first: Pull back and
hold the brake release handle, and slowly press the pedal up and
down a couple times near the top of travel, observing the warning
light like a hawk. If it remains on at the exact same intensity, the
parking brake switch warrants further inspection. If the light
changes in intensity even slightly as the pedal is operated, the
parking brake switch is probably not the cause (light is already on
due to another cause, becomes brighter due to two ground paths).
Next try pulling the
pedal back slightly beyond its top-stop with the top of your toes
while pulling on the release. If this cancels the warning light, the
switch requires adjustment or repair.
Now it may be time to
get a little dirty and torque your back! Unplugging the single wire
leading to the parking brake switch will cancel the light if it is
the offending part. Sometimes these primitive switches come loose or
fall apart, or if the wire leading to it becomes snarled in the
ratchet mechanism, the resulting grounded circuit will turn on the
light, likely intermittently.
Q: I was just told
when having my tires rotated on my Yukon 4x4 that my right front
wheel bearing was loose. Being an old timer, Iíve done wheel
bearings before. I was surprised to see there isnít a dust cap as
Iíve had in the past. What gives?
ó Carl G.
A: Your Yukon, like
other GM light trucks, utilizes an integrated hub/wheel
bearing/brake sensor assembly. Previously quite expensive, these
hubs have come down to the $100 to $150 range for a name brand part
(donít go cheaper). Installation requires a little over an
hourís labor, some large wrenches/sockets, and a few choice words.