battery going flat during day intermitant

Nev2xs · Post by **Nev2xs** » Tue Oct 30, 2012 9:07 am

My 1990 mx5 drains the battery during the day while I am at work intermitantly
battery is new
will do it 2 days in a row and then not for a month
I am thinking alternator reg
is there a diode in this that is an easy change
what can you suggest
thanks Nev

Nearly too late · Post by **Nearly too late** » Tue Oct 30, 2012 5:16 pm

Check that your headlight dip switch is not faulty and leaving the headlights on high beam.
My 1990 5 has this problem and only happens every now and then.

WideOpenThrottle · Post by **WideOpenThrottle** » Tue Oct 30, 2012 5:35 pm

Got clean & shiny terminals & connectors plus tight connections?

I had to put a spacer in my positive connection.

SLYDIT · Post by **SLYDIT** » Tue Oct 30, 2012 7:11 pm

normally when you pull back on the light stalk to flash your high beams the little plastic spring returns it to the off position. the plastic spring can lose its tension and your high beams can come on for no reason. if you do not have the "flash to pass" diode fitted the lights can be on but the pop ups stay closed. only fix is to glue a small shim on the spring ring to give it a bit of preload.
my car did this and i never noticed. it only did it on hot days...the plastic must soften.

battery going flat during day intermitant

battery going flat during day intermitant

Who is online