Hi All

My 2003 TL Magna AWD has developed a problem over the last few months... Here goes -

Firstly the battery light started flashing every so often, eventually this turned more regular. I put the car in for a service, the alternator tested fine and needed a new belt (which I had replaced) but was told the battery needed replacement soon.

After another couple months, it started flashing up basically the whole dash (ABS, brake, oil, battery, SRS) and when this happens the a/c turns off and sometimes the radio as well. I replaced the battery last week with a new one thinking it would fix the problem but it still intermittently flashes all the warning lights and cuts out the a/c - The car seems to keep driving fine...

I have noticed as well that if I have the a/c on full and I am driving it's fine, but when I stop at traffic lights or the idle drops the a/c fan speed drops down low (even when on full) and then when I take off an accelerate it will increase back to normal...

I was thinking maybe an earth problem, but it's so intermittent I can't show the mechanic.

Suggestions anyone? or has anyone had this problem?

This is very common alt issue, bad diode and you get over charge

I would start with teh alt and go from there

At the first flash of the alternator charge light you should have replaced the alternator or at least removed and inspected it. Often its just the brushes that wear out initially. Left for a while longer the diodes go and the regulator goes out too, from the voltage and current surges when the brushes loose contact with the armature. At the very worst the alternator will allow battery current to flow backwards and flatten the battery. If you find the alternator warm or hot to the touch when the car hasn't been used for a few hours you will know what is going on. lol


In short, replace the alternator and all will be fine.

Thanks for the helpful advice, I will take both your words and get the alternator replaced first... Just confusing how it was tested and I was given a print out stating it was all good?!?

Have just tried to book it in but my mechanic is closed until 10th of January, guess I will get the old man to give it a bash over the next few days

Thanks again!

wow thats like dejavuh (if thats how you spell it) i had exactly the same issue with my 2000 magna sports (th) replaced the alternator and all was good again. even gained a bit extra grunt :D

Oh god... it continues...

Finally got it in to my mechanic today, they told me over the phone it would probably be the regulator so I booked it in.

Anyway they looked at it, tested the alternator - charge tested, drain tested, battery test and starting test all is perfect, I even have the print out which reads all good. So they gave it back to me and said we couldn't find anything, you'll have to try an auto electrician if it keeps happening. Whatya know, drove it out 5 mins down the road air con cuts out and the dash lit up like a Christmas tree.

Just curious, if it was the alternator/diode/regulator should that have appeared on the tests today?

Hmm if it an intermited problem give the alterantor a hit with a hammer seem if it comes good, then hit it again see if it goes bad. This how my alterantor play up lol You only need to hit it lighty not to take out your angry out onto your alterantor lol I really hate intermited problem as they take forever to fix and cost dearly :(