oil pressure guage

[Lugnut]

1. Oil pressure guage on my '83 J-truck(360ci)not reading since the bodyshop guy pulled the instrument panel out when he painted the dash (well, heck, I did change paint colors-didn't wanna leave the inside the old color). Anyways, I've replaced the sending unit with the proper guage-type sending unit and still not working. I noticed there are 4 pins sticking out the back of the inst. panel in the area of the gauge, the socket that plugs into the four pins has contacts in three of the four holes, and there are two wires going to that socket. I've looked around under the dash and can't really spot any stray wires hanging around. I'm not even sure these 4 pins have anything to do with the oil guage. Not being terribly good at auto. wiring, I really need help trouble-shooting this. I don't like the idea of driving around and not knowing my oil pressure situation.
2. I've also noticed there is a sending unit for a "light" in the same fitting on the engine block as the other sending unit. I've checked my inst. panel and don't see a place for an oil pressure light. This engine came out of a '78 Wag. originally and I don't know if that vehicle had both pressure indicators on the dash.
I promise pics. one day when I can afford one o' those dijitol camera thingys. I'm kinda proud of it.

[porchpiggy]

Sorry, can't help with the particular wiring, but I noticed the comment about the second sending unit for a light. I thought this when I first saw the second electrical unit in line with the oil sending unit, but, (if it's what you are talking about) the small round one is actually tied into the electric choke. :cool: