Questions and Answers

Dodge Ram 1500 No Cruise, HVAC Problem
Q. Sir, I have a 1996 Dodge Ram 1500, 2WD with a 3.9 liter V-6, P/S, A/C and cruise control. My truck has 124,000 miles. Two problems:

1. My cruise control will not work. The light on the steering wheel comes on but it will not set at any speeds. What should I inspect?
2. While traveling with my heater or A/C on, with the selection on vent, when I accelerate the blower switches from vent to defrost? The dealer tells me this is normal for Dodge trucks? Is this true or is there something I can do to correct the problem?

Thank you,
Duane

A. I believe both problems are related and the cause is a vacuum problem.

Look at the Cruise Control Servo located under the battery and check the vacuum lines. Battery acid drips down on the servo and eats the vacuum line away, causing a vacuum leak.

Since the HVAC controls are vacuum operated as well, this leak will affect the air flow position.

If you find that the vacuum hose is damaged, there is a special repair procedure and new parts to repair and prevent this problem from happening again.