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Old 29th June 2016, 06:58 PM
RichardH RichardH is offline
Senior Member
Join Date: May 2015
Location: fife scotland
Posts: 177
Default mx5 alternator testing

my 1.8 mx5 engine 1999 is not charging, i suspect the alternator is faulty but there isnt much about testing them , i have 12v on the heavy cable which comes from the battery via main fuse, i would expect this to rise to 14v ish on startup but it doesnt.
the plug onto the alternator has two wires a grey and a grey/red, i have 5v on the grey and nothing on the grey/red, from the web i reckon the grey/red should have 3 v AC ???? as a signal to the ecu. before i cough up for another alternator anyone any ideas
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