I was working on my car tonight and must pulled the oil sending unit wire off, I get in car and oil pressure is buried, maxed out. so I look and sure enough the wire is off, I hook it back up, but no change, guage is still buried, What could be wrong now ? would the guage go bad that quick, or the sending unit ? where or what should I check first, and how do I go about it ? I hate electrical problems.