E320 CDI Air Conditioning New Noises

[Paul P]

Hi guy's any ideas. (E320 CDI 210 year 2000 estate) We had a towbar wired up by a auto electrician that we found in the yellow pages .An hour after he left we went to the car and turned the ignition on and we herd a click and a blower buzzing sound by the air conditioning unit, on the dashboard it came up Battery/Alternator visit workshop, I managed to contact the auto electrician he said disconect the negative lead on the battery for 5 mins and then reconnect it, we have done this the battery warning symbol on the dashboard went out but when you turn the key to the start position you hear a click sound and then all the warning lights dim slightly as if there is a lot of power been drained out of the battery .I took the lid off the air conditioning box in the engine compartment and you can feel the air blowing out cold straight away can any body help please Paul (up to having the tow bar wired we have had know problems)