JimF-thank you for recommending my site to other board members

And ASR and Non-ASR switches work the same- one opens and other closes. Reading are similar on both, just don't remember them out my head now.

According to my diagram taken from Mitchells switch S1 is closed on idle and S2 is open on idle. And it's opposite when throttle is opened. There is something wrong with your ETA. I just fixed one customer ETA who had similar issue.
In Non-ASR ETA switch S1 is under linkage side cover, there is a microswitch there that you should hear clicking when you move linkage to park. There is a distinctive click.
Switch S2 is on the other side. There is no audible click and that switch is very hard to get to-gear, spring, clutch gear. Then there will be potentiometer block. S2 switch is incorporated into that block. To get inside one has to drill out small brass rivets and be extremely careful not to damage sliders.
I hope this helps.

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1999 ML430 Silver 135k ml
Smoked LED taillights, Alpine in-dash DVD player, 12" sub, Pioneer components, 2 amps, 4200k HIDs, ML55 headlights, 20" rims, mirror LED blinkers

SOLD. 1996 E320 145k ml. Burgundy

SOLD but miss it everyday 1992 500sel Black
Chime buzzer mod,Alpine CD/MP3 player with stock amp,Euro headlights,S600 grill,20" rims, BEST CAR EVER!

SOLD. 1990 300E White
187k ml,smoked tails,Euro headlights,17rims,Intake,12" sub in first aid kit,alarm/autostart,buzzer mod