QuestionI have a 92 Dodge Caravan 3.0L. We replaced the engine last year. My cruise control worked up until we replaced the engine. We checked the fuse box: fuse is good but there is no electricity in #14 slot. I have read my Hanes book many times to figure this out and there is no page that shows the electrical for the cruise control. It says check vacuum hoses, switches, and connections. I have no idea where these things are located. Can you help me PLEASE?
AnswerHi Tina,
The 12V supply voltage for the system is indeed supposed to come through fuse #14, but you would only find it to be present when the ignition switch is in the run position. So do verify that, although there are so many other systems and fuses that need the same supply line I don't think you will find it to be missing. Check that when you have 12V on one side of the fuse it also appears at the other side; a fuse can look good but have a nearly invisible crack in the wire.
The speed control depends upon a cable between the servo unit and the throttle valve at the air intake throttle body on the engine. So to find the servo begin by looking for a unit under the battery tray. It has electrical wires, a vacuum hose, and a mechanical cable that runs to the throttle valve. If the person who installed the engine forgot to connect the cable to the throttle valve lever that would explain why you have no speed control. The mechanical cable comes out of the "snout" of the servo unit.
If that is connected at the servo and the throttle valve lever (you can find the throttle lever by having a helper operate the gas pedal while you observe for something that moves on the engine at the read end of it), then check the soft rubber vacuum line at the servo which should also run to and be connected with several other vacuum operated devices at multi-outlet port on the air intake manifold of the engine. That outlet can most easily be located by tracing the large rubber hose, that runs from the brake booster cannister located at the fire wall directly in front of the driver, back to the engine. There you should find also a nipple that has the vacuum line from the cruise servo attached. Check that vacuum line all the way to the servo for cracks or a disconnect at either end.
Write me back if you find the mechanical cable connection and the vacuum line appear to be ok. The next steps are to go through the electrical connections and switches for possible failure that could cause the system not to work. That will take several steps to complete.
But it seems to me with this history of it being related to replacing the engine that the most likely cause is the throttle cable connection or the vacuum line because those would have to be removed to take out the engine and replaced when the new engine was installed. The electrical are not so intimately associated with the engine proper.
Roland
