Cruise control intermittently stops

[Ted Couch]

When traveling in our 1989 Beaver Marquis the cruise control will suddenly stop working. Sometimes I can reset it and other times I have to just let it go and try again later. This is one of those annoying intermittent issues that makes RV-ing so interesting. Anyone else have this happen, and if so, did you find out how to fix it? Thanks.

[Steve Huber Co-Admin]

Ted,
I think your coach may have a Bendix CC unit. It uses air pressure to operate. You may have an air leak in the system. You can find a diagram in Coach Assist wiring diagrams, Beaver Coaches 1968-1994, Service Manual/Schematics.
Steve

[Frank Bergamo]

Ted,
I had the same problem with my 86’ Executive Diplomat. As Steve said, I believe you have the Bendix CC. The problem on mine was low voltage at the control module. Mine was set up with the 12 volt source running to the rocker switch by drivers seat, then back to the control module. Finally realized that I was losing voltage in the long run of wire. I installed a relay switch close to control module, using the rocker switch as the trigger for the relay. Used starter cable from battery, for 12 volt source to relay, then to control module. Worked like a dream, never had a problem again. If your control module is the problem, there is a guy in Dallas that can rebuild it. I don't think that is your problem, as it seems to work at certain times. Hope this helps.

[Mandy Canales]

I had the same problem with my Bendix CC on my '90 Marquis and finally it quit all together.  I let it go for 4 - 5 years before I wanted the CC working again.  I had it worked on several times by different mechanics but  to no avail.  I finally bought a Universal CC and had it installed.  It didn't work either after installation.  The mechanic finally decided that the speed control module going into the tranny was faulty and replaced it.  Now it works like a charm after $3 grand out of pocket.  He couldn't tell for sure but thinks it was speed control all along.