Jump to content
Server maintenance Read more... ×
Sign in to follow this  
RAWDEAL

DC 5.0, Trying to wire a relay to turn on when the engine is on

Recommended Posts

Hi guys i am trying to find a wire that will let me trigger a relay so that when the engine is on , the relay is , even when just cranking

 

I am not sure how to go about it without having a wiring diagram or manual on hand?

 

the oil pressure switch would be the opposite to what i want as its only on when low oil pressure ?

 

I did use the red coil wire but because of the pulses it diddnt work, it just went bezerk lol

 

anyone got any simple ideas on where i can get some +12?

Share this post


Link to post
Share on other sites

Alternator warning light circuit should do it.

 

Get it directly from the wire at alternator plug.

 

Alternator warning light gets 12V+ into one side and 12V- the other side so it will light up when the ignition's on and the alternator isn't turning.  When the alternator is turning it will then push out + instead of negative.  Two positives won't light the lamp, hence the lamp goes out when alternator is turning or the engine is cranking or running.

 

When static, the wire will give negative feed to illuminate the warning lamp, but when the engine's turning it will change to 12 Volt + output.

 

What type/model of car is it..?  I should be able to tell you which colour the wire at the alternator is.

Share this post


Link to post
Share on other sites

its a 1993 dc ltd! with the 5.0 in it 

 

So basically want 

 

Car off > Circuit open

Car on/Cranking > Circuit closed

 

Not sure which wire on the alternator to splice into ill have to have a look tommorrow

Share this post


Link to post
Share on other sites

Try oil pressure switch hooked up to the NC terminal (87a) on a changeover relay. Get power to the relay from ignition not battery. That's failing the above method anyways.

Share this post


Link to post
Share on other sites

Splice into the fuel pump relay circuit.

Fuel pump only runs when cranking, engine running, or for a few seconds when ignition is turned on.

 

I would but i am using it to bypass the headfkuc that is with the current LPG wiring , and rewiring the lpg system

 

Atm it works on petrol, but doesnt work when flicked onto gas. Just gonna get an auto elec mate of mine to rewire it for me 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×