[AllanC]

Can anyone tell me if the cruise on an 1988 Caravan (Plymouth Voyager) comes with a small vacuum reservoir attached to it?

I used to own a 1988 Dodge Caravan and I do not remember a vacuum reservoir attached to the cruise servo. In addition I owned a 1989 Plymouth Acclaim and the cruise servo was a different style with a different electrical connection from the 1988 model. So there was a design change in the servo electrical between 1988 and 1989 models.

The donor vehicle from which you salvaged the cruise servo may have had parts applied to it from a different model year.

 

[ImperialCrown]

A dealer installed Mopar cruise control might have been different than the factory installed cruise.
All vehicles should have a vacuum reservoir for climbing hills with cruise engaged. The plastic battery tray lower portion doubled as a vacuum reservoir for many different years and models.
The brake light switch may also be different.

 

[slim slow slider]

OK, thanks for the info. Too bad the issue is so clouded.

I guess I can't go wrong using the setup from an 89 w/ cruise. There's a tiny vacuum reservoir attached, and the four-pin plug matches the plug in the wiring harness.

Thanks to all for your help!