I just replaced the Water Pump on my 1987 190E 2.6

(nightmare). The car has been sitting in my driveway for 5 months. After completing this, lucky me, the ABS light is on, it idles really low, (close to stalling) and it is very hard to start when the engine is not warm. I have pretty much determined that this is most likely because of the OVP (Overload-Voltage-Relay), or it's fuse. I just wanted to see what other people thought about this.
Thanks.