[DeTomaso] Bad ignition switch?

[JDeRyke at aol.com]

The ignition switch can have two different kinds of problems- mechanical 
and electrical. You seem to have both, in different parts of the same switch. 
The return-spring issue is likely due to either no grease in the mechanical 
part of the switch- especially around the steering lock lug going into the 
shaft, or old grease thats turned to concrete. This usually cannot be 
corrected from outside the switch. To access the spring and work with the grease, 
you must DRILL OUT the two broken-head 'security' screws holding the switch 
to the steering column. You'll also have to drill out the screws if you 
decide to re-key the same switch. Std metric screws will fit after removal.

The electrical issue could be a burnt contact inside the electrical part of 
your switch, which is removeable with two different non-security screws 
holding it to the main switch. Once the electrical part is off, you can clean 
up the contacts and decide your next move.

Unfortunately, as I outlined in the illustrated POCA Newsletter article in 
the June 2012 issue, there are a myriad of slightly different switches 
available from all over the world, most of which will not just plug into your 
wiring. I suggest you re-read that article first, and refer to the photos 
comparing what you have, as a baseline. Your serial # implies a late '73-early 
'74 car but that doesn't narrow things down much. The major vendors have 
rebuilt switches of several types available, but a good photo of the switch you 
now own would be helpful when/if you call them. 
Good luck- J Deryke. POCA Tech Editor