1998 Cadillac Deville, Passenger Side Vents Hot with A/C On

This 1998 Cadillac Deville came in with the complaint that with the a/c on there was heat coming out of the passenger side vents. Codes B1340 and B1341 were present in the HVAC system. Both codes are for faults with the air mix door actuators. The B1340 is for air mix door #1 (driver’s side) and B1341 is for the air mix door #2 (passenger’s side).

The passenger side air mix door actuator is located behind the glove box. There are four screws around the face of the glove box opening that have to be removed. A torx bit is needed to remove these screws.

There are two on the bottom surface of the glove box. I had to use a ratcheting wrench with the appropriate bit to remove the two screws on the bottom.

Once all six screws are removed the glove box insert will pull free of the dash. There may be several wiring connectors that have to be disconnected on the left side of the box. Sometimes there will be foam stuck to the right side of the box that may make it difficult to pull from the dash.

With the glove box fully removed I could see the link arm (horizontal rod) and the actuator. The rod position in the picture below is for full cold.

The rod position in the next picture is for the full hot position. It was easy enough to diagnose the actuator as being the actual problem because the actuator would try to move when commanded but I could visibly see and hear the gear teeth stripped out as the mechanism jumped and chattered. A slight helping hand in the correct direction and the actuator would move correctly.

The harness connector for the actuator is located at the edge of the actuator closest to to firewall. There is a thumb latch that has to be depressed and then the connector will lift straight up and out.

There are two screws that hold the actuator to the HVAC case. They both have 5.5 mm heads. The next picture shows the location of the left screw as indicated by the socket that I placed on it.

The screw on the right side of the actuator.

The threaded rod will lift out of the white clip with just a little bit of help.  Sometime the clip may be a different color. Pay attention to the position of the rod in the clip.

Once the rod is removed from the clip it can be squeezed together  and pulled out of the actuator arm.

The new actuator is on the left and the old one is on the right. The number on the old one is 16180230. The new one has the same number computer-etched into the plastic along with “Made in China”. Both are ACDelco parts. I know that there are both good and bad parts made in China but ACDelco partners with quality manufacturers and has the parts made to their specifications. I trust this process a lot more than just buying brand X, manufactured to unknown specifications.

The genuine ACDelco part can be purchased here 16180230 . You may want to buy two though because the driver’s side will be failing soon.

To access the driver’s side actuator, remove the three 7 mm headed screws that hold the hush panel in place under the passenger side of the dash

With the hush panel removed the driver’s side actuator can be changed in the same manner as the passenger side.

To adjust the door link rods GM states to adjust the temperature to full hot. Once the actuator stops moving move the rod to the position that allows full heat to come from the vents for the appropriate side. Then snap the link rod into the plastic clip. Quite frankly, if I am relatively sure that no one has adjusted the link before I will just put it back into the same position I found it in. After all it worked fine for sixteen years.

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