where is it located on a 1988 300e

Beneath plastic computer cover just behind the battery.

Looks to be in the film on the passenger side fire wall. There is a picture of it in the online catalog if that helps at http://www.peachparts.com/catalog either look it up by application or type the part number in search by part number. Rember if you click on the picture it will go to bigger size.

thanks for the info

As indicated, behind the battery, the OVP relay is the one with the fuse on top.

Good luck,