How much should it cost to have mechanic diagnose problem w / cruise control

[monkeyplanet]

for 2007 Scion Tc? One mechanic says he'll take it apart to see where the problem is, and that will cost me $65. As far as how much the whole job will cost, he said he couldn't even begin to estimate til he knows the problem. Should I do it? Any ideas about the price? Thank you.