1990 Voyager cruise control

Looking for some suggestions about an erratic cruise control.....

1990 Plymouth Voyager 3.3 auto

When I first turn the cruise on and set the speed it will usually run
OK but only for about 5 minutes or so. It will then generally just
quit, as if I turned it off, but sometimes it will just gradually lose
speed. Once this starts to misbehave, it won't set and maintain a
speed again, at least not for quite awhile.

I know that there are 2 main parts - a "valve box?" and a vacuum-type
part that has the cable to the accelerator block, both located just
about under the battery.

Any suggestions about what I could try to help decide which of these
parts is not operational?

I had an old Toyota with cruise once and the rubber in the vacuum
piston had gotten old and cracked and so cruise stopped working on
that. Toyota wanted about $300+ for a replacement part which included
stuff I didn't need.....so I did without cruise.... :-(

Dave

 

Sounds like a vaccum leak to me. A vehicle of its age can develop a
defective hose to the vaccum reservior, the reservior could be brittle
and cracked. Make a visual inspection of all the elements and consult
the shop manual (if you have one) for more troubleshooting. Cruise
problems can be easily detected, at least from my experience, anyway.
Good Luck! Hope this is a good start to resolving the problem.

 

There are many main parts, the servor,the speed sensor, the brake switch,
the cruise control switch, the vaccum supply and circuit harness. Instead
of guessing at the problem, take it to the dealer or whoever and ask them
to see what the last cruise control cut out was in the Monitored section
of the Scan tool while it happens. In other words if you are using the
cruise control and it cuts out for no reason at all the Engine controller
will see what made it turn off.If it shows the brake switch did it and you
know the brakes werent applied then the switch would be faulty, and so on.

Glenn Beasley
Chrysler Tech