See my latching relay as per
on/off latching circuit with 2 relays.
The diodes are not required if the switch handles the load current (until the relay closes).
The
Fused +12V would be your normal supply to the a/c switch (ie, ign +12V).
The N.O.
push to turn off is only needed if you want to turn it off without removing the input
Fused +12V.
And as
Ween suggested, I'm assuming this is for the "master" a/c
enable circuit - not the compressor itself - hence all pressure switches, idle-speed drop outs, cycle delays, etc, continue to operate normally.
Thanks for the clarification.
Ween & I saw "
A/c compressor" and assumed it was for an aircon.
The diagram I linked - namely...
... will work fine but with a few provisos...
Keep both diodes unless the ON switch can handle the compressor current. Hence the switch and its wiring need only be rated for the relay's coil current.
If you don't want to be able to manually turn off the compressor (with IGN still on) the OFF switch can be omitted - ie, merely have the "feedback" wire with diode.
The +12V input needs to be IGN switched. (If it's to constant battery +12V it won't turn off.) That may require an (extra) IGN +12V relay (with fuse) if existing sources can't handle the compressor current.
FYI - the ON switch's dashed wiring to "+12V" was dashed for simplification. In its original form (ie, as per
here; Reply #7) the ON switch's +12V could be from another source - eg, HU remote output or other
enabling circuit.
There are alternative circuits which IMO are more attractive
if the additional 2nd relay is needed (I dislike using multiple relays for what I consider to be single relay circuits... or paraphrased, I prefer using solidstate circuitry for logic and leaving only using relays to handle the power switching), but that latching relay circuit is simple and suited for
non-electronic DIY types. (FYI - I originally devised it for a water pump after only finding equivalent circuits that used totally unnecessary additional electronics!)
Thank you for your reply. I think that is what I was looking for.
Floyd
Never mind. I didn't see the requirement ot turn it off with the IGN still on.