minated, the FCM is programmed to suppress all rear washer requests in order to give priority to the vehicle oper-
ator’s need for forward visibility.
Washer fluid is gravity-fed from the washer reservoir to the inlet port of the washer pump housing. An integral valve
body is located in a housing on the outlet port side (2) of the pump housing. A diaphragm (4) in this valve body
controls which washer system plumbing receives the washer fluid being pressurized by the pump. When the pump
is not operating the diaphragm is biased to close all washer fluid flow in the rear washer system and, in this way it
also performs the function of the rear washer system check valve.
When the pump impeller (1) rotates in the counterclockwise direction (viewed from the bottom), the biased dia-
phragm is sealing off the rear washer system outlet and nipple so the pressurized washer fluid is pushed out
through the pump front outlet port and the front washer outlet nipple (5). When the pump impeller rotates in the
clockwise direction (viewed from the bottom), pressurized washer fluid is pushed out through the pump rear outlet
port and moves the diaphragm to open the rear washer outlet nipple and seal off the front washer outlet nipple, then
the pressurized washer fluid is pushed out through the rear washer outlet nipple (3).
The windshield washer pump and the hard wired motor control circuits from the FCM may be diagnosed and tested
using conventional diagnostic tools and procedures. However, conventional diagnostic methods may not prove con-
clusive in the diagnosis of the SCM, FCM, CAN data bus or the electronic messages used to provide windshield
washer pump control. The most reliable, efficient, and accurate means to diagnose the SCM, FCM, CAN data bus
and the electronic messages for the windshield washer pump control requires the use of a diagnostic scan tool.
Refer to the appropriate diagnostic information.
REMOVAL
1. Disconnect and isolate the negative battery cable.
2. Raise and support the vehicle.
3. Remove the liner from the left front fender wheel
house.
4. Disconnect the wire harness connector (1) from the
top of the windshield washer pump (2).
NOTE: To aid in reinstallation, note the installed
position of the washer hoses prior to disconnect-
ing them from the windshield washer pump.
5. Disconnect the washer hoses (3) from the barbed
outlet nipples of the windshield washer pump and
allow the washer fluid to drain into a clean con-
tainer for reuse.
CAUTION: Care must be taken not to damage the
reservoir during windshield washer pump removal.
6. Using a trim stick C-4755 or equivalent, gently pry
the barbed inlet nipple of the windshield washer pump out of the rubber grommet located on the reservoir (4) and
remove and discard the rubber grommet.
8R - 54
FRONT WIPERS/WASHERS - SERVICE INFORMATION
WK