On Sun, 13 Aug 2006 19:10:47 +0100, steve
<
[email protected]> wrote:
>Tom Woods wrote:
>> On Sun, 13 Aug 2006 18:35:55 +0100, steve
>> <[email protected]> wrote:
>>
>>>> Can any vehicle wiring gurus tell me if it is possible for me to use a
>>>> single 4 pin relay and have it both going on with +12v from the
>>>> ignition switch and off with +12v from the LPG controller?
>>> No, you wire the 12v feed to the pump through the (normally closed)*
>>> switch contacts. You wire the LPG cutoff to the coil of the relay.
>>>
>>> *Normally closed - as if the coil is switched off, the contacts are CLOSED
>>> c.v. Normally open, as if the coil is switched off, the contacts are open.
>>
>> So use 2 relays then?
>>
>
>No, just the one - you only want to isolate the pump when the LPG is on
>don't you ? The pump HAS to run when you're on petrol.
I was thinking that the pump would be effectively turned on by an
ignition live trigger from my ignition switch (and possibly an
imobiliser switch) - ignoring the LPG; the act of turning the pump on
with the ignition was going to use a relay.
I was wondering if i could turn the pump off, (or prevent it turning
on from the ignition live trigger) using the 12v LPG active feed along
with the SAME relay.
I could do it with 2 relays, one that turns on with the igntion and
another to cut the feed as you describe but it would mean less relays
if i did it with a single one.
would the following work? :
assuming the relay has 4 pins which are coil 1 and coil 2 (C1, C2) and
then power 1 and Power 2 (P1,P2) which are the 2 contacts on it. (the
pin numbers pdf at AES is down

)
C1 - ignition live +12v from ignition switch via imobiliser
C2 - +12v from LPG switch (to fuel cut/active)
P1 - +12v
P2 - Fuel pump
When the ignition was turned on and the LPG was off the pump should
run (wire to LPG presumably 0v/Gnd).
With the ignition on and the LPG on the pump wont run.
am i right here?
otherwise i need to use 2 relays.