Triggering negative switching from positive?

[SimonInAustralia]

I have just had a Harrop (Eaton) ELocker installed into the front of my HZJ78 Troopcarrier.

I would like the factory dashboard front locker light, in the combination meter, to come on when I activate the ELocker.

The Elocker has it's own loom to power the ELocker with positively switched 12V DC.

If I want to turn on the negatively switched dashboard light with the ELocker circuit, I assume that I have to put in a relay to switch the dashboard light circuit to negative, using the positive of the ELocker circuit to turn the relay on.

Would this be right?

Is there an easier way than wiring in a relay to negatively switch the dashboard light on?

 

[ntsqd]

Does the Elocker use a relay for it's own controls?

If so, modify the harness to draw power for that relay to come from the light you wish to turn on when you flip the switch. This would put the light, the switch, and the relay in series, so the light may be a bit dim depending on the total resistance of that circuit.

 

[dieselcruiserhead]

Yes wire it positive if you can. But if you want to do a negative switch, then simply use a relay... A relay can carry either negative or positive current via the 30/87/87a circuit. I hope it helps...

 

[alia176]

If the Elocker uses a single pole single throw (SPST) relay, then you can change it out for a double pole single throw (DPST) relay. Use one set of contacts to activate the locker while use the other set of contacts can be used to activate the dashboard locker light. The DPST simply eliminates the use of a second relay for the dashboard light; it's like having two SPST relays into one.

I hope I didn't confuse you!

 

[SimonInAustralia]

If the Elocker uses a single pole single throw (SPST) relay, then you can change it out for a double pole single throw (DPST) relay. Use one set of contacts to activate the locker while use the other set of contacts can be used to activate the dashboard locker light. The DPST simply eliminates the use of a second relay for the dashboard light; it's like having two SPST relays into one.

I hope I didn't confuse you!

Didn't confuse me at all, thanks for the advice, sounds like a good idea.