[busnut]

You don't really have a cruise control, but a computer. The DDEC controls everything. This is a case of really checking out all your connectors. You may want to unplug everything and replug.

'94 model Newell came with 8V92TA with Allison 740 and a couple had WT4000. Some 94s had Series 60 with Allison 740 or WT4000.

Both engines had DDEC or ECM (engine computer module), but the 740 did not talk to the engine. Instead you had speed sensors. Don't recall if the sensor was in the transmission or mounted on the drive shaft. The Allison WT4000 had a TCM (transmission control module) and carried on a conversation with the ECM.

Anyway the cruise switch by the driver tells the ECM how fast you wish to travel.

So you have an ECM problem. Hopefully a bad connection somewhere in the system.