Re: where is the overvoltage relay
The overvoltage relay should be located directly behind the battery in the engine compartment. It is silver in color with a red top that flips up to expose a fuse on the top. To the left of the Overvoltage Relay is the Fuel Pump Relay, which is black in color. Prior to replacing the Overvoltage Relay, check the fuse to be sure it's not blown. If memory serves me correct, the cost on Fastlane (which is the best) is around $60.00. If this doesn't work I would replace the Fuel Pump Relay (about $70.00 at Fastlane) . I had a similar problem on my 1985 190e, and it turned out to be the Fuel Pump Relay.
Let us know how it goes.
1990 BMW 325i