1990 Bonneville lock up

Got a -90 bonneville SE that not will shift in to lock up...
all other gears and od works but not lock up.
are there any cheap and simple solution aviable or is the tranny shot?

Scanning it will tell you if the solenoid is being activated, if no lock up either the torque convertor is bad or the solenoid is not actuating.

Scanning it will tell you if the solenoid is being activated, if no lock up either the torque convertor is bad or the solenoid is not actuating.
Thanks for the reply...
Where is the solenoid located and from where/what is it triggered?

The pcm looks at engine speed, load and and an open brake switch circuit and grounds the solenoid in the trans side cover.