Supplement to Bulletin 05-01-37-002A, Poor Rear Heat Performance - keywords 2nd 3rd aux auxiliary core heater HVAC idle pump row seat

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

The information below may be helpful prior to installing an auxiliary coolant pump. 1. Auxiliary pump was installed into production vehicles starting in early January 2005. (Bulletin 05-01-37-002A applies to vehicles built prior to early January 2005) 2. When diagnosing a poor rear heat concern, it is important that the correct mode is selected in the rear HVAC.

1. Beginning early January 2005, the auxiliary coolant pump was installed in vehicles during production. Prior to ordering a auxiliary coolant pump from bulletin 05-01-37-002A, inspect the vehicles door sticker. If the door sticker shows a build date prior to January 2005, a auxiliary coolant pump can be installed. On any vehicle build in January 2005, it will be necessary to see if the vehicle in question has an auxiliary coolant pump installed during production. If the vehicle is equipped, bulletin 05-01-37-002A does not apply. The auxiliary coolant pump can be located in the lower right rear of the engine compartment under the coolant recovery tank and near the HVAC coolant by-pass valve.
2. When using the auxiliary rear heat, it is advised to select the "FLOOR" mode for best results. Selecting the "VENT" mode offers a longer travel path and there is more potential for heat loss prior to the air discharging from the roof vents. This is a normal operating characteristic and no repairs are recommended.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.