Re: Getting a small 12 v timer - home elelctronics?


"Scott" <scott.lewis@xxxxxxxxxxxxxxxxxx> wrote in message
news:43B66E05.6080907@xxxxxxxxxxxxxxxxxxxxx
> Hi Paul,
>
> Do u think the relay is actually working as the manual option is pushing
> power through the prestart relay, yet i think with the original setup, i
> can hear the click but nothing else, so was thinking that maybe its not
> getting its 3sec burst of power to heat the plugs. Is this hence
> controlled by the relay control unit?

Scott.

If you can hear the relay coming in to play when you turn the key, the
actuating coil inside the relay is most probably working ok. The weak point
in any relay is the contact points and the actuating linkage from the coil
to the contacts.

If you can, pop the cover off, give the contacts a clean. With a test
meter, identify that 12 volts is present on one side of the relay contact
and when closed, 12 volts is passed to the output side of the relay. If you
can see the relay operate and can prove that the relay is closing correctly,
and passing voltage, then you can be assured that the relay is in all
probablility operating correctly.

Also be aware that the glow plug time varies with the ambient heat of the
engine. On a cold day the woofer can hold the relay in anything up to a
minute. In warm weather, 15 seconds at most. This on time is controlled by
the ECU and information it is receiving from temp sensors fitted to the car.
It may look like a short time the relay was engaged but this may be correct,
or a premature turn off caused by an errant sensor elsewhere. As a side
note, my 05 X-Trail DCi needs more cranking when cold than my Y plated 25TD,
funny how the older design engine is an absolute brick in all weather
conditons and the X-Trail needs longer coaxing, design being design I guess.

My personal guess is that the relay contacts are dirtied and need a look at
before going elsewhere. Check the voltage is actually passing through the
relay bfore you completely exonerate the part.

PDH


.

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