I have a rebuilt chassis computer from a forum member and it has been in my car for a little over 2 years. now all of the sudden all of my warning lights will come on but only when my headlights are on and when the motor is cold.

My car's voltage is usually at 13.8-14.0v during normal driving day or night. but when the lights are coming on i have noticed that the voltage is higher usually between 14.4-14.7v these reading are taken via an Apexi turbo timer plugged into the ignition wiring.

Also the lights are not coming on and staying on the a flickering one and off very quickly for a bout 1-2 seconds then it stops for anywhere between 10 seconds and 5 min then they will start flickering again and this will continue until i either turn off my headlights or the car heats up to operating temperature.

Do the warning lights all come on when the voltage is to high as well as to low i have never heard of anyone with this problem before.

BTW i have an FD alt but I'm not sure that matters as it has been in the car for over 4 years with out a problem.

 

the fact that it doesn't occur when it's at operating temp. and that it flickers wants me to not say that it is the alternator; but, when my alt. went bad all the warning lights would come on and stay on. could there be a short, or bad wiring going to the box?

 

Its been my experience that Apexi turbo timer and AFC's are notoriously bad for voltage readings. Get a digital multi-meter and confirm the voltage as well as AC voltage at the alternator.

14.7 volts is too high.

That and the flickering of the idiot lights suggests that you probably have lost at least one of the rectifiers in the alt, but it is also possible that the CPU could be bad.

Only real readings with a real digital multi-meter are really going to tell you

 

Ill try taking a reading with a multimeter tomorrow with the lights on. the problem is that this is intermittent so i might have to wait a day or two before it starts doing this again.

Ya i know that 14.7 is getting dangerously high thats why i was thinking that maybe the voltage regulator was going out but that wouldn't explain why my idiot lights are flickering.

I can also hear what sounds like relays clicking on and off the same speed of the flickering but i just figured that was the relays for the lights.

EDIT: Icemark you have a PM

 

Ok bring this back from the dead:

My idiot lights stay on almost all the time every once in a while they'll turn off. Once they are off ill get to a red light and take it out of gear they come all back on. My car Is an 86 with s5 turbo stock engine. Alt is new and belts are new what else can it be??

oh and i did search but they all said change the alt or belt

 

Well they all said to replace the alternator because that's probably what it is. I went through TWO kragen alternators before finding 1 working (and more expensive) one from napa. Both of the first ones had bad regulators (right outta the box) that would put out a max of 13.0V. With a load on them, the voltage would drop below 12.0V, and drain my battery.

Test the voltage with a multimeter at the alternator + post and at the battery. My bet is you'll see that it's not making near enough power.

 

i'll give that a try but i have 2 brand new alts from mazda dealer and the batt is new aslo but ill see what i get on the dmm so its suppose to read 14 for the lights go turn off?

 

Hmm, if they're new factory alternators, they've got a good shot at being ok. But the thing is that warning lights come on as a well...warning...that the regulator is bad. You'll probably see different voltages at different times (regardless of load), but it'll be due to the regulator not being able to properly maintain the correct amount of current/voltage.

Here's a link to troubleshooting for an S4 NA, but the gist is the same for a turbo. http://mazdarx7.iougs.com/electrical.shtml

I don't know of one for an S5, but the bottom of the page will tell you the difference between the two alternators.