brake wear warning light wires are a constant problem. On all the CXs
I've ever purchased these wires were broken or removed. If the wires
are broken the owner never knows because the light will generally not
come on. However, when the wires are removed I know the light was coming
on, but falsely, and this is the mechanic's permanent remedy.
These wires light a warning lamp on the dash when the pads are worn
to their minimum thickness. The lamp is lit by the wires grounding
to the rotor, completing the lamp's circuit. This is a very effective
method for warning the driver of impending trouble and saving the cost
of a new rotor! The fact that it is troublesome is because few mechanics
can be bothered to route the wires carefully when replacing the brake
pads, and even when they do the wires still become chaffed and light
the lamp falsely.
This page attempts to show a remedy for this arcane problem, for those
who want to have everything working on their car, and working reliably.
Clearances between the brake calipers and wheels are quite close, so
the routing of the wires from the pads is critical. Also, the factory
chose a wire path which results in breakage, no matter what is done to
prevent it. I'm rather surprised a bulletin was never issued to correct
this problem since nearly every car had to suffer it at some point, and
surely Citroen dealer mechanics, and factory mechanics, must have noticed
and commented on the problem. Oh well, we'll fix it for sure here.
you can see, this path takes a bit of a circular route around the
pivot of the lower arm and goes up the side of the 'tower' on the
But the real problem lies in the bend at the lower
ball joint. This photo clearly illustrates the problem because
these wires are broken in the classic way.
Here we see an overview of the essentially original brake wire
path. The wires are caught under the anti-sqeal spring (here a
slight modification is made, a sheath keeps both wires together).
The two wires travel over the top of the spring as they leave
the rotor area, a common mistake which will probably result in
chafing of the wire against the wheel.
The wires connect to a pair of bullet plugs, then travel under
a clamp and over to the other side of the steering knuckle, down
the knuckle and along the lower arm.
you cannot see the break clearly just click the photo to see a
larger image (all the images are linked to larger copies). As you
can see, this break is complete. We could fix it, but that really
means running new wires since a fix in this stressed area will
quickly break again. We could put a splice in the vertical section
behind the brake duct (not shown) but again, we'll get the break
again in a few years, or less at this very spot!
We need a good permanent solution and that means re-routing the
wires to avoid this severe bend. The photos that follow show just
such a route. Is it the only new route? No, but it has proven to
work well on other CXs we own. We have actually used two different
routes and are tracking their effectiveness over time, but this
one mimics other cars where wires are taken out to the steering
knuckle without failure (a French car at that!) and is the easiest
of the two routes to run. See update below for our progress in monitoring the wire's longevity.
So here is the new route from the caliper. This
is the opposite side's caliper on the same car, for reference.
Also note the odd connectors, the previous owner's mechanic had
completely removed the original wires. We are using standard bullet
connectors found in any U.S. auto parts store. They have to be
closed up slightly to grip tightly, and we'll be covering this
connection with heat shrink tubing (it was left open for this photo). Notice
the wires exit the caliper by passing under the spring.
If you don't have the original wires you may be a bit confused
about how to wire them. Inside the engine bay are two wires, near
the sub-frame, one green and one brown, twisted together. The brown
wire runs ground to the steering knuckle and is bolted to the steering
knuckle with the bolt holding the wire clamp (you can see the ring
connector in this photo). The green wire runs to the pads, it splits
into two connectors just after the wire clamp. Both wires run through
this route we've chosen to run the wire in front of the upper ball
joint. This puts it perilously close to the rotor, so clamp it
well to prevent movement. Since the wire and steering knuckle move
this does not pose too much of a problem.
the wire is run along the brake hose, wire tied to it in two places
and also wire tied at the top, to the brake line. Simple enough,
don't you think?
UpdateRecently we pulled the two front wheels off our CX Safari. One side, the
passenger side, the wire ran loosely from the steering knuckle to the subframe, separated
from the brake hose by about 3 inches. On the other side the wire ran alongside the brake
hose, wire-tied to the brake hose. This wire run was broken at the last wire tie, which was
on the brake line below the joint to the steel line. The break occurred because of another
tight turn here. We'll be re-doing that wire to mimick the other side which as proven quite
reliable. I will post photos of the two runs when I get them.