nsxb23136a.pdf

Engine Coolant Temperature (ECT) Gauge
ECT Gauge Test
1. Before testing, check the No. 5 (1 5 A) fuse in the
under-dash fuse box.
2. Make sure the ignition switch is OFF, then discon-
nect the YEL/GRN wire from the ECT sending unit
and ground it with a jumper wire.
YEL/GRN
WIRE
ECT SENDING
UNIT
3. Turn the ignition switch ON (II).
Check that the pointer of the ECT gauge starts mov-
ing toward the “H” mark.
CAUTION: Turn the ignition switch OFF before the
pointer reaches the “H” mark on the gauge dial; if
you don’t, you may damage the gauge.
• If the pointer of the gauge does not swing at all,
check for:
— An open in the YEL or YEL/GRN wire.
— Replace the ECT gauge if the fuse and wiring
is OK.
• If the ECT gauge is OK, check the sending unit.
ECT Sending Unit Test
1. Disconnect the YEL/GRN wire from the sending unit,
and with the engine cold, use an ohmmeter to meas-
ure resistance between the positive terminal and the
engine (ground).
2. Check the temperature of the coolant.
3. Run the engine, and measure the change in resis-
tance with the engine at operating temperature
(radiator fan comes on).
4. If the readings you get are substantially different
from the specifications above, replace the ECT send-
ing unit.
YEL/GRN
WIRE
POSITIVE
• TERMINAL
ECT SENDING
UNIT