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350matt
350matt, Engineer - BEng Hons
Category: Saab
Satisfied Customers: 20963
Experience:  Mechanical Engineer with 20 years experience in the auto industry, 8 yrs in formula 1 engine testing
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Got a Saab 2003 9-5 Aero Wagon. Car had been doing quirky

Customer Question

hi got a Saab 2003 9-5 Aero Wagon. Car had been doing quirky things for about a week...ac shut0ff no reason etc. then all indicator lights came on loss of power and it stopped. A diagnostic check indicated the battery was ok. checked old alternator and
it was putting out only 7 volts. Removed old alternator and noticed wiring had burnt lookand it turned out to be corrosion, proceeded to clean off and put new alternator. After running a few minutes the same failure mode occurred and the new alternator went
to 7 volts. Took the old alternator to Autozone and it tested good. Where does the problem lie, Could a bad wire cause this problem? William d cowie
Submitted: 1 year ago.
Category: Saab
Customer: replied 1 year ago.
Hi can you estimate how much longer Thank you
Expert:  350matt replied 1 year ago.

Hello William

yes bad earth can cause this issue so I'd suggest cleaning all the earth connections on the battery and on the engine where the large earth wire connects the battery earth to the block / gearbox

then there will be some other small wires that are earthed onto engine, these are for the low current ECU circuits and again they must be clean, free of corrosion and tight

also check the resistance of the main earth strap / wire as it shoudl be only a few ohms at the very most any more than this and it should be replaced

Expert:  350matt replied 1 year ago.
Hello
do you still need help?