Are you sure you really arent over heating? The best way to check is to run the car with the computer attached so you'll end up reading the temp straight from the engine instead of the guage. The grounding points on a dse as far as I can remember are under the fuse box near the battery. there...

Check the thin hoses going into the fuel filter. Had the same symptoms on my dse. Engine would turn over but wouldn't fire w/o any dash lights coming on. Felt as if no gas was getting in. Hoses were almost unplugged from the nipples letting in air in the system. easy check.

Hi this happened to me as well on my range rover dse. temp guage will jump to 3/4 whenever I opened the a/c especially on climbing. Temp will immediately fall to normal upon turning of the a/c. Turned out to be a bad ground. Check the main ground connection from the battery to the inside fender...