[DeTomaso] Turn Signal Question

[J. Sean Keane]

I recently discovered that while the turn signals on my '74 L-model 
work, they do not stay locked in position.  The signal only functions as 
long as I physically hold it down.  When I let go, it immediately 
springs back into position.  Is this something that can be fixed without 
replacing the unit?  If not, where is the best place to get a 
replacement unit and about how much should I expect to spend?

Regards,

J. Sean Keane