Technical Wiring Question

Looking for confirmation on wiring up relays.

-I have 2 relays, 1 for electric fan and 1 for fuel pump. Both wiring diagrams show a pink wire to “Keyed on Switched Power”

-I have a a spare circuit on my fuse pane labeled “Spare Ignition Accessory Lead”

It seems like this would be an appropriate power source?

Thanks




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Check it with VOM, if it has power only when the key switch is 'on' then you're good to go. Best to check everything as these old cars have had lots of electrical 'improvements' over the years and labels are subject to interpretation.

 

Those are two items you probably don't want to run when the ignition switch is in the accessory position, which is usually for radio, power windows etc.


Phil

 

If you have a four-position ignition switch (off, on, start, and accessory) I'd also check to make sure that wire is only hot when the switch is in the 'on' and 'start' positions, not 'accessory'.

 

Depends on what the pink wire is for on the relay, ***uming it's the wire that turns on the relay should be fine (not the power supply for what the relay is turning on). And like oj said check it with a voltmeter or test light, for the fuel pump I'd only want power in the ignition position on the key switch not in the accessory position.

 

What Steve said in reply #4 and to confirm. The most simplest of all tester's.

 

Acc position IS switched power, live when the key is in the on position. I would use it to power the relay as the relay isn't using a large power load to trigger it. The relay turns on after it's fed power and powers up whatever you've chosen for it's use.
The difference between acc and ign on the ign switch is the acc side is shut totally when the switch is off, where the ign side can be byp***ed by current allowing the car to run when ign is switched off. Acc is what I use to power relays, I'll wire the feed to the alternator off the acc position because, like I said, switch the key off, acc is dead and won't allow power to flow around it.

 

For most relays operating non-engine-related bits, that's correct. But most ignition switches disconnect the accessory terminal when turned to 'start', so that would kill your fuel pump. And if you decide to just listen to the radio, do you want the fuel pump and fan running?

 

There are never radios in my hot rods......and you're right about the fuel pump, hadn't thought of that.