Anyone got any ideas why the following multiple electrical problems happening on a 1996 Disco Mark 1? Converted to LPG.

Where to start troubleshooting for these problems?

1)When parked, if we open driver's door the interior light goes off (rather than on like you'd normally expect). If passenger door opens first before driver's door light goes on in the interior normally, but goes off if drivers door is opened.

2) Also Erratic speedo. Sometimes works sometimes doesn't register anything.

3) headlights, right hand driver's side headlight is dimmer than the other one until it has warmed up maybe some 10-15 minutes.

4) Uneven running and tendency to miss, or even stall. When it hiccups sometimes it stops running on LPG

5) Air con stopped working but seems quite possible this problem is linked to all the other electrical glitches.

 

the speedo issue is likely the VSS ....vehicle speed sensor located on the transfer case

headlights....check the 3prong connector at the bulb...probably corroded and/or burnt

uneven running.....most likely needs a complete tune up....plugs, plug wires, filters, oil change and a good lookover....any CEL codes ?

the door light has me baffled....sounds like the door light switch (which can be a SOB to work with) may be shorting out.....try to pull it out with thewire attached tosee if the wire is grounding on the frame....and good luck,as the wire there is usually really short