1989 Jaguar XJS AIR TEMP

REX L MORGAN

MEMBER
1989 JAGUAR XJS
V12
2WD
AUTOMATIC
95,000 MILES

Can anyone explain how the air temp switch on the air filter works? It has two wires going to it it seems to me the wire with voltage should give the other wire voltage at a certain temp. When the motor is at opperating temp there is no signal or continuaty between tabs that come out of switch. Also the water temp switch does'nt seem to ground at full temp is this correct. Thanks Rex

1 Reply

DAVE H

MECHANIC
13,384 POSTS

XJS AIR TEMPERATURE SENSOR TEST
Disconnect battery terminals and air temperature sensor connector. Connect an ohmmeter between sensor terminals. Ohmmeter reading should vary with temperature. Refer to the XJS AIR TEMPERATURE SENSOR RESISTANCE table in this article.
Check resistance between sensor body and each of the terminals. Resistance should be high or infinite. Replace sensor, if sensor does not test okay.
XJS AIR TEMPERATURE SENSOR RESISTANCE
Temperature °F ( °C)Ohms
14 (-10)960
32 (0)640
50 (10)435
68 (20)300
86 (30)210
104 (40)150
122 (50)108
140 (60)80

XJS COOLANT TEMPERATURE SENSOR TEST
Disconnect battery ground cable. Remove connector from temperature sensor. Connect an ohmmeter between sensor terminals. Resistance should be as specified. Refer to the XJS COOLANT TEMPERATURE SENSOR RESISTANCE table in this article.
Check resistance between each of sensor terminals and sensor case. High or infinite resistance should be present. Connect sensor connector and negative battery cable.
XJS COOLANT TEMPERATURE SENSOR RESISTANCE
Temperature °F ( °C)Ohms
14 (-10)9200
32 (0)5900
50 (10)3700
68 (20)2500
86 (30)1700
104 (40)1180
122 (50)840
140 (60)600
158 (70)435
176 (80)325
194 (90)250
212 (100)190