A class elec probs

[krmoto]

hi, l have just found this site and reading back through the threads there is a fair chance someone will have some clue's of what the hell is up my wifes A class 17 CDI avantguard semi auto (98) 55k.
this car seems to have a mind of its own as far as elec's go, but the latest thing is it won't crank over and the cooling fan is running when the ign is on, it has done this before and seemed to clear itself after l fitted a new battery,
also recently it has been running on sort of half power but if you get it warm then stop it lock it/unlock it then it usually will run normal, there has been other things that have happened over the years which l think are all to do with the main fault whatever it may be. hope someone can shed some light on it.

 

[Cole@MBS]

Welcome to the site,

If the cooling fans are running with the Ign on,the car is losing the commutation with the engine control module, the fan control module then puts the fans on as a safety issue!

Check the connections to the engine ecu and the earth points, sounds like there's something loose or dirty!

 

[krmoto]

ok many thanks for that,
l will get straight back under the bonnet when the big freeze lets up a bit.

 

[lofty]

While your under the bonnet check for abrasion of the cables coming to and leaving the ECU for examples of the problems experienced by owners see my page 54 there is every chance that you have a broken cable where the loom has been damaged.
http://www.aclassinfo.co.uk/mypage.54.htm
It would also be worth checking the plug that goes to the varible fan controller on the face of the rad.

 

[MB TECH WARRINGTON]

ive had a cooling fan faulty cause this.

 

[krmoto]

thanks chaps, l got plenty to go at now.

 

[krmoto]

is there anything that connects the no cranking over thing and the electric windows because they are not working but all else seems to be, except for the pre heat for starting.

 

[krmoto]

also before l had a new alternator fitted, if l operated the drivers window when the car was at low rpm it would start to run very lumpy like as if that door motor is faulty, the other doors don't affect the engine running. so at the moment l have disconected the motor.