My 1990 RS is the same way. The problem with it is the steering is loose. If I push the wheel in at about the 9:00 position and then hit the high beams they work. Its not the switch the steering has loosened up. Apparently its a common problem. I plan on tearing it down in a couple days.

 

Not much to tear down there bud, just the panels under the steering column, and then the two 10mm nuts that hold the steering column. Column drops right down, and the dimmer/high beam switch is towards the back of the column on the drivers side.

 

Those two nuts that hold the columns bracket are a lot bigger than 10mm
And that is not how you fix the loose column. To fix that, all the top of it has to come apart. Farther that replacing an ignition lock.

 

My bad, I didnt read it all and was thinking he was still talking about the dimmer switch...

And btw, I remember for a fact that the nuts on my column bracket were 10mm, maybe it changed..? [&:]

 

You are reffering to the nuts that hold the U shaped braket that has four bolts on it that holds the column up? If so you are going to have to check that again. The studs may very well be a 10mm but the nuts, or in some cases bolt heads are larger than a 10. Maybe you had to chase threads and used a 10mm tap

Ohh the four, five or so screws that hold the plate to the firewall are 10mm headed.

 

No, I remember it very well, two 10mm nuts holding my column up.

 

I want a pic!