Axle Temperature Gauges (Forward And Rear); Testing The Axle Temperature Gauges - Volvo VNL Service Manual

Group 38 Instrumentation, VNL, VNM
Axle Temperature Gauges (For-
ward and Rear)
Fig. 63: Front and Rear Drive Axle Temperature gauge
signal flow
Fault Indications
A constant gauge reading of 32
caused by a defective sender unit or gauge, or an open
wire between the cluster and the sender unit.
A constant reading of 130
caused by a defective gauge or sender unit, or by a wire
that is shorted to ground between the gauge and the
sender unit.
Inaccuracies greater than 12
defective sender unit or gauge.
52
W3000715
 
C (90 F) or less can be
 
C (270 F) or more can be
 
C (10 F) usually indicate a
Testing the Axle Temperature
Gauges
1 Make certain the vehicle ignition is OFF.
2
CAUTION
When servicing or troubleshooting, do not leave
the cluster face-down for more than 15 minutes,
or damage to the gauges may occur. Gauge oil
can run out the front of the gauge faces and
make the gauges inaccurate.
CAUTION
When probing connector terminals, do not insert
probes into the terminals. This will spread the ter-
minals apart, causing permanent damage. Probe
the insertion side of the connector.
Gain access to the rear of the instrument cluster.
Disconnect connector RX and measure the resis-
tance between harness pin 13 (Front Axle gauge) or
pin 3 (Rear Axle gauge), and pin 11 (ground):
Axle Temp.
 
21 C (70 F)
 
50 C (120 F)
 
95 C (200 F)
3 If the resistance readings are correct, reconnect the
connectors and turn the key on. There should be
battery voltage between connector RX pins 11 and
14. If not, and the rest of the cluster works, the wire
from RX-14 is probably open.
4 If the readings are off more than 10%, the sender
unit should be checked. The sender is mounted on
the axle. Refer to the VNL, VNM Electrical Schemat-
ics for wiring information.
Troubleshooting
Expected Reading
1000 ohms ±10%
430 ohms ±10%
110 ohms ±10%