Meza,
Thanks for your advice. I tested voltage & got -386.9mV, & got zero (0) reading for mA. Then I checked my printouts from the Forum & , to test the OVP, put the red in pin 3 & black in ground. The DMM read 1.7, which probably means the OVP is dead because that is the same reading I got from my 1991 300e from which I had pulled the OVP. Unfortunately, I can't swap the OVP because the newer one has 7 pins (& 2 fuses) & the old one has only 6 pins ( & 1 fuse). Although the fuse was changed by the PO 1 yr ago right before I got the car because the ABS light was on, I'll change the fuse & see if the reading changes; otherwise time to buy the OVP.
Rich