I'm having this weird problem with my oil pressure sender. I converted 85 glht to smec and used the later style all in one sender/switch. Is the L body cluster not compatible with the newer switch/sender? For some reason the light will come on and the gauge will just drop down to 0 when its warmed up even though I put a mechanical gauge on and it reads about 15psi hot idle (see video). I ghetto rigged the original old style single wire switch into it and the low oil light never came on. So I figured my sender/switch was bad, bought a new one but it does the same thing. As far as the gauge, it's almost like the new style sender has a much lower operating range. It either reads right in the middle or nothing.
http://vid272.photobucket.com/albums...psfmjinkcb.mp4