T15 switches - what's what?

I finished putting the tranny back together and I can't remember which switch does what of the two located on top of the shifter plate. Both of my old ones are pretty beat up. I'm sure one is for reverse lights, but what is the other one for?Was this that weird attempt at early emissions control that never really worked? I read about it somewhere, but can't find it now. In any case, I need to know which one is the reverse light switch and where to find a replacement part. Any assistance is appreciated. You all have been extremely helpful and responsive so far - thanks!

 

Yes , the switch on the passenger side is for the reverse light. You can see the activator move when shifting into reverse.

The drivers side switch is for the Trans Controlled Spark. It was supposed to activate in third gear, to cut vacuum advance at low RPM/high ported vacuum situations.IIRC

 

Napa has replacement switches. I don't have the part # handy but a search should turn it up as it's been posted several times.

 

Certainly the reverse switch is available. The TCS switch may not be - as I recall, it's a different design with a single wire. I expect you could use the reverse switch for TCS if you change the plug and add a ground lead.

Nothing wierd or failed about the TCS - it did what it was intended to do and reduced emissions. There's no story attached to it, other than it was part of the emissions compliance equipment from that era.