Toyota Repair: cruise control, good luck jack, speed signals

Question
I have a problem with the cruise control on my 1998 Corolla.  When ascending a hill the automatic transmission shifts down to second gear.  After it levels off or begins to descend it will not shift back up to third gear.  I have to disengage cruise and re-engage to make the shift. Any ideas? Maybe a simple adjustment somewhere?

Answer
I have to assume that you have a factory cruise control. One way you can tell is if when the cruise is on a green light will come on the dash saying the cruise is one or a factory looking switch is on the dash panel.
If the cruise does not come back to life after you level off the cruise  control computer may be at fault. There was a problem with these but normally not in the Corolla. There can be some other reasons so before you go replacing parts I suggest that you visit the local Toyota dealer. They can connect a scan tool that will tell them how the various senosrs are working that should be sending the speed signals to the cruise computer.
Good luck
Jack