I have just finished the wiring of the Off Timer Relay from Waytek. It was a little confusing to me, but Chuck got me started and I now understand it. Here is the data page from Waytek.
I chose the 75543 relay because it gives a good range of time to choose from.
Here is the way I wired it.
*The 87A terminal has to be wired as a switch. It is the deactivation(turn off) that starts the timer sequence. If you wire it so that the ignition turns off all your switches when you turn the key, it will start the timer from that point. If you wire the switch from continuous power, you will have to manually turn it off to start the sequence.
*The 86 terminal is for a ground wire that is interrupted by a switch to start the sequence. So you have a choice of wiring the activation mode, either positive or negative(not both).
The one thing I am not sure about is, if you use the negative terminal with a switch, do you use constant power to 87A??? I never wire a relay this way so I don't know if this applies in this case? Electronic guys???
*The 85 terminal is wired to ground.
*The 86 terminal is a 15amp fused constant 12 volt source(hot all the time).
*The 30 terminal is wired one of two ways. One is it can go directly to the source(fan(s), pump,or both). Since this is a relay you can chose this route. I chose to wire mine to the coil circuit of another relay that will control the two 5" fans in the engine bay. They only draw 5 amps each, but I feel better this way.
When I tested the relay and fans, it worked perfectly. The timer was set for 1.5 minutes(you don't know because the timer has no pointer). You have to use a tiny screw driver to adjust the time. It seems like there ought to be a button with a pointer on it, but it doesn't, so you have to trial and error it to get the time you want. Jack and some of the others have theirs set at 2 minutes. I am not so sure that is enough, so I will start with 3 and see. If it needs adjusting I can do it easily enough.
I want to mention in passing that whenever I add a circuit, or completely wire a car, I use a 12 volt power supply to test the circuit(s). Mine is a Pyramid 6 amp unit
pyramid 12 volt power supply - Google Product Search
and they come in different amperages. All come with circuit breakers and it makes a safe way to test any circuits you are building/adding before attaching that 150 amp battery. If there is an error, or a mistake, or a wire comes loose, the circuit breaker could save you a whole wiring harness.
Bill