Red light and alternator

[moggiegeek]

I have had two aftermarket alternators from a popular supplier. The first suffered from dodgy diodes - as diagnosed by local friendly car electrical workshop. the second was a direct replacement but now it too seems to be failing.
I get faint red light on all time at normal running speed which gets brighter as engine revs drop.
The fan belt tension seems OK and the alternator is wired in as per instructions
Any hints and tips appreciated for tracking down the fault.

[mike.perry]

I had the same fault on my Maxi years ago, I just ignored it and the car kept running

[bmcecosse]

Send it back for a refund! There have been MANY complaints of faulty alternators - I suspect all from the same source... To test it - you need a voltmeter - should show 13.8/14 volts at the battery at decent revs - and hold that when the head lights and heater fan are switched on.

[kennatt]

as above,straight back, more than a few faulty ones about.Its probably the control unit inside the alternator.