Honda Repair: 1994 Honda accord oil light, oil pressure switch, oil sending unit

Question
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Followup To
Question -
1994 Honda accord oil light
this weekend I had my oil changed. after driving about 50 mi my oil light came on. I stopped at the nearest store and put a quart of oil in because i thought maybe the people forgot to tighten something. however that was not it. after sitting for a few hours i drove home slowly (about 12 mi) and when i got home my light came on again. Then in the am i left for work, went by the mechanic who was not open, so i went ahead to work and drove 20 mi, came home drove another 20 mi got home and the light came on again. if someone knows what this problem is so i can get this fixed. the mechanics have several different answers. i appreciate it.

Answer -
Patty:
The oil light is directly related to the oil pressure in your car and if you do not have any oil pressure you can severely damage your engine. Since you just had your oil changed I would bet that the oil filter is bad, otherwise it could be your oil pump.
Good luck.
Bill

your information is good, i appreciate it.  you mention that the oil filter would be bad - when i just had it changed?  i guess i don't understand that.  i have had 2 mechanics tell me it would be the oil sending unit but you think it is the oil pump.  your thoughts?
thank you

Answer
Patty:
The oil sending unit (oil pressure switch) is screwed into the engine and detects the oil pressure, if the oil pressure is low it turns the light on the dash on. If it is detecting low pressure, I am assuming that there is no (or very little) oil pressure and therefore it would be the oil pump. If you oil filter is bad that can also cause low pressure and of course the sending unit itself may be bad, so I stand corrected (or at leased added to).
Bill