An open in circuit 476 (BN/YE), 468 (BN) or 676 (PK/OG)
A short to ground in circuit 468 (BN) or 476 (BN/YE)
Solar radiation sensor
Electronic automatic temperature control (EATC) module
PINPOINT TEST D: DTC B1259 OR DTC B1261 — SOLAR RADIATION SENSOR OPEN CIRCUIT OR SHORT TO GROUND
Test Step
Result / Action to Take
D1 CHECK THE SOLAR RADIATION SENSOR RESISTANCE
Ignition OFF.
Disconnect: Solar Radiation Sensor C287.
Measure the resistance between the solar radiation sensor terminals 2 and 6 and
between 1 and 2.
Is continuity present and the resistance greater than 0 ohms?
Yes
GO to
D2
.
No
INSTALL a new solar radiation sensor and bracket. CLEAR the DTCs. REPEAT the
self-test. TEST the system for normal operation.
D2 CHECK THE EATC MODULE OUTPUT VOLTAGE
Ignition ON.
Press the AUTOMATIC button.
Measure the voltage between solar radiation sensor C287-1, circuit 468 (BN) and
C287-2, circuit 676 (PK/OG).
Measure the voltage between solar radiation sensor C287-2, circuit 676 (PK/OG) and
C287-6, circuit 476 (BN/YE).
Are the voltages between 4.7 and 5.1 volts?
Yes
GO to
D7
.
No
If diagnosing DTC 1259, GO to
D3
. If diagnosing DTC 1261, GO to
D5
.
D3 CHECK CIRCUIT 468 (BN) AND CIRCUIT 476 (BN/YE) FOR AN OPEN
Ignition OFF.
Disconnect: EATC Module C228b.
Measure the resistance between EATC module C228b-6, circuit 468 (BN) and solar
radiation sensor C287-1, circuit 468 (BN).
Measure the resistance between EATC module C228b-18, circuit 476 (BN/YE) and
solar radiation sensor C287-6, circuit 476 (BN/YE).
Yes
GO to
D4
.
No
REPAIR the circuit for an open. CLEAR the DTCs. REPEAT the self-test. TEST the
system for normal operation.
Page 13 of 45
2006 Town Car Workshop Manual
12/30/2011
http://www.fordtechservice.dealerconnection.com/pubs/content/~WS6G/~MUS~LEN/19/...