On which side of the oil filter (inlet or outlet) is the oil pressure sending unit on a 2001 Dodge Dakota 4.7?

 

As is normal, the pressure sending unit is located on the output side of the oil filter (real close to where the oil enters the motor)

 

I used synthetic my last oil change. I am going for 7K, and I haven't changed the filter. The oil pressure gauge still reads right on the line before the high mark, so I wanted to make sure it's not just my oil filter clogging up.

 

I've heard (and agree with) that if you plan on doing extended service intervails with oil (over the normal 3-4 thousand) its a good idea to change the filter at 3-4 thousand.
Until you take the filter off and actually cut it open, there is no great way to know how clogged the filter is. Oil pressure, theoretically, could tell you, but you must remember, oil filters have a bypass valve that will open up if the filter is clogged (because non-filtered oil is better than no oil ). It's the same thing on the planes I work on, except we have a little indicator that will pop-out telling us the filter is in bypass-mode (and we do engine checks almost after everytime our planes fly).