wbrian63: I believe that the switch does not control the transmission; it’s the other way around. The switch closes when the transmission initiates a gearshift; this signals the EZL to retard timing for 400ms thereby reducing torque output.

Mike Freeman: That’s a great idea – it will confirm that 1.) The wiring is O.K., and 2.) That the retard function is working. Plus, it should throw the diagnostic code that the switch “does not open” versus the “does not close” code that I’m currently encountering. Good point on the o-rings – if they are leaking, then perhaps the switch isn’t seeing the proper hydraulic pressure. (?)

I’ll crawl under there tomorrow and try it out…

__________________
Current rolling stock:
2001 E55 183,000+ Newest member of the fleet.
2002 E320 83,000 - The "cream-puff"!
1992 500E 217,000+
1995 E300D 412,000+
1998 E300D 155,000+
2001 E320 227,000+
2001 E320 Wagon, 177,000+

Prior MBZ’s:
1952 220 Cab A
1966 300SE
1971 280SE
1973 350SLC (euro)
1980 450SLC
1980 450SLC (#2)
1978 450SLC 5.0
1984 300D ~243,000 & fondly remembered
1993 500E - sorely missed.
1975 VW Scirocco w/ slightly de-tuned Super-Vee engine - Sold after 30+ years.