Based on the electrical manual, the two items appear similar, but not the same. Note that pin 4 is an output on the 190E relay and an input on the 190D version. This may cause problems if you plug in the wrong relay.
The RPM output isn't shown on the 190E relay either...
Here's the comparison:
Code:
Pin 190E-2.3 1985 190D-2.2 1984
1 Ground Ground
2 RPM Input Engine RPM Input
3 --- Engine RPM Output
4 Compressor Engaged (output) WOT Input
5 Power Power
6 --- ---
7 Compressor Clutch Control Compressor Clutch Control
8 --- ---
9 Compressor Speed Input Compressor Speed Input
10 Air Conditioning Control Air Conditioning Control
11 Compressor Speed Input Compressor Speed Input
12 Temperature Input ---
Edit: What I'm comparing here is the A/C compressor control module for each model of car, under the assumption that these parts fit in the same socket. I haven't actually seen the 190E version or verified the part #... Also, in some places they call it a "refrigerant compressor relay", other places it's a "refrgerant compressor and kick-down cut-off control module", etc. which makes it a bit confusing.