Do you have the problem?
The usual symptom is an inability to effectively control the temperature in your car. Note that this symptom can also be caused by a bad temp control knob, and this is a common failure on Ford trucks. Please check carefully before considering the blend door fix.
The blend door hangs on a vertical axis, so turning a sharp corner, or fiddling with the fan speed can swing the door into the hot or cold position randomly. While the symptoms are fairly conclusive for blend door failure, the only way to really check it out is to remove the blend door actuator motor and look at the axle.
Another reported symptom is a clicking sound coming from the actuator motor. This occurs when the motor gears get out of alignment and are slipping against each other, making the noise. Sometimes you can make it stop by pushing down on the back of the motor and getting the gears to catch. The failure usually occurs with a broken blend door that allows the motor to get out of alignment and twist slightly, causing the gears to disengage. Heater Treater will put the system back in alignment and correct this problem.
Chrysler two different HVAC systems on the early Grand Cherokees. You need to check the application information below carefully to make sure you know which one you have.
There were two main systems used for the GC:
- The earlier system has the blend door actuator motor on the bottom of the heater box. The motor is located under the passenger side dash, above the transmission tunnel. Open the passenger door and kneel to look under the dash. You will most likely have to pull back the carpeting on the left side to see the motor. It will be attached to the bottom of the box. A picture from a box that was removed from a GC is shown for reference.
- Some XJ’s, particularly the dual control systems used the later design which was continued through 2004. This system has the actuator motor on the front of the box behind the glove box opening. You will need to empty and fully open the glove box to see the motor. On the right side of the box there may be a dampening assembly. Remove this by pulling the attachment up and out. (This is a miki-mauze assembly and was eliminated on later models. Our recommendation is to pull this out and throw it away. Consider this as an upgrade to the older system.)
With the box half open, you will see two black rubber stops inserted into the dash frame. Pull these straight down to remove. Watch carefully how they come out since they have to go back the same way. You can re-insert the stops with the glove box fully open and the glove box will slide past the stops fit properly. The actuator motor is in the upper left hand corner behind the glove box. A picture of the motor is included for reference.
This kit is for the earlier (#1) above system. If you have the second type of system, check our 98-04 Grand Cherokee listing for the correct fix.