Batery not charging, and engine temp increase.

Evening all.

The lil Jim has developed a really odd and utterly annoying fault. The other day I left the lights on and the battery went completely flat. I jump started it and left it too idle for an hour, but as soon as I turned the lights on, it would cut out (was dark out) and the battery was completely dead and would not take a charge.

Ive had a new battery fitted as the old one was suspected to be dead. Vehicle ran for a while, but the battery light came on and the engine temp gauge shot up. Limped it back to the garage and discovered the alternator was not charging.
Had the alternator sent off for testing and was returned with no faults found. Had it refitted and the fault was still there.

Had an auto electrician take a look and check the charging circuit today and found a fault that was said to have been fixed.

This evening I picked up the vehicle, which seemed fine at first, but once the engine was up to temperature the battery light came on again and the temp gauge started to go up again. (Though a lift of the bonnet showed no signs of overheating).

Im a little worried i may have damaged the ecu through jump starting, or would there be a relay or fuse that has been damaged?

Im stumped, as is my mechanic.

Has anybody else had this problem? Or know of anybody who has? Just want my Jimny back

Is your alt belt snapped or slipping ?

check the ECU earth on the engine if this is not good can play havoc with the temprature gauge as i beleive its fed via the ECU had this when i fitted my diesel and didnt reconnect the ECU earth on the engine it is located near the temp sender unit as for the altenator im guessing you have no exciter voltage gettin to the altenator with out this it will not charge in the same way a altenator can not charge a battery from flat as its predersesor the dynamo could

No problem with the belts, fan is functioning correctly. The temp gauge would drop once the vehicle was stationary, but didn't need to turn it off. Also there was no sign of anything actually overheating.

Dave cc wrote: check the ECU earth on the engine if this is not good can play havoc with the temprature gauge as i beleive its fed via the ECU had this when i fitted my diesel and didnt reconnect the ECU earth on the engine it is located near the temp sender unit as for the altenator im guessing you have no exciter voltage gettin to the altenator with out this it will not charge in the same way a altenator can not charge a battery from flat as its predersesor the dynamo could

Shall suggest this tomorrow.