I have a 1989 burban. I was trying to install the oil pressure sending unit for a autometer gauge and i am having a little trouble. I checked the top of the block near the distributor but could not find the factory sending unit. The only sending unit i saw had three wires. i didn't have the best light either though. Does anybody have a diagram or anything like that so i could get a better idea of the exact location. i haven't been able to get under the hood much lately because of the weather (way too cold in vermont for a geargia boy) so i didn't have the light and time to really look so any help would be greatly apreciated.