1994 Jaguar XJ6 heater

DEEREMAN1969

MEMBER
1994 JAGUAR XJ6
6 CYL
2WD
AUTOMATIC
11,800 MILES

Yes I am having a problem with my heat on my car, it seems that possibly the blend doors are opening then closing off after 3-4 seconds only allowing cold air to be moved thru out the cars cabin. Heater hoses entering the car at the heater core are at operating tempurature. A.C. Works as it should any ideas were to locate my problem?

Friday, December 4th, 2009 AT 8:16 PM

1 Reply

DAVE H

MECHANIC
13,384 POSTS

INOPERATIVE AUTOMATIC TEMPERATURE CONTROL
Defective in-car sensor. Defective coolant thermostat. Defective CCU. Defective servo control. Defective vacuum actuators. Defective control panel.
SYSTEM SWITCHES MODES DURING ACCELERATION OR UPHILL DRIVING
Vacuum leak in vacuum reservoir tank. Defective vacuum check valve (located near engine, in vacuum supply line). Leaking vacuum hoses. Leaking mode switch.
SYSTEM WILL NOT SWITCH MODES
Vacuum supply loss from engine to firewall connector. Vacuum supply loss from firewall connector to control panel mode switch. Defective CCU. Defective vacuum solenoid. Defective mode switch. Binding linkage or stuck air doors.

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Thursday, December 31st, 2009 AT 7:39 AM