Toysonly

Hey just wondering if anyone’s found a way to make the headlights turn off automatically in a 90 pickup? My 95 4Runner had it and I’d like to make the pickup do the same it’s a dlx, just swapped the wiper/headlight controls from a 94 to get the wiper delay that was plug & play. I don’t know how the auto headlights work, anyone know? Is it just in the switch? Do any 3rd gen pickups have auto lights? Or just 4Runner? Only sr5?

RAD4Runner

You want the headlights on ONLY when Ignition is on even if engine is off? Take headlight relay CONTROL/coil voltage from IG pin of ignition switch.
You want the headlights on ONLY when ENGINE is on? Take headlight relay CONTROL (coil) power from "L" fuse of charging circuit. That has 12V only when engine is running and alt is working normally.
Remember, use only the 12V power from IG pin or "L" circuit to power the relay coil, no the load contacts.

scope103

The trick with "auto-off" headlights is that you don't want them to turn on until the engine is running and putting out power from the alternator (otherwise, you could just hook the headlight relay to IG1, they would turn on with key-on, and the headlights might pull enough current to keep the truck from starting in cold weather). That's why RAD4Runner suggests using the L circuit of the alternator (he says "L" fuse, but on my '94 the alt light is power by the IGN fuse, which is 12v with key-on. I'm sure he means the L side, not the fuse side, of the alt light.)

But hooking L from the alternator directly to the headlight relay will keep you from using the headlights when the engine isn't running; L is pulled to ground when the alternator is not producing power.

So ... move to Canada! Canada required DRL (Daytime Running Lights) back when our trucks were built (all cars sold in the US now have DRL), so Toyota had a special box that used the L circuit.

Or build your own DRL circuit. You just need a few diodes and an FET or two, and passive components and a circuit board .....

OR ... try this: https://www.aliexpress.com/item/32832257840.html I haven't installed mine yet, but on the bench it does just what it says. You don't need to use the L circuit; it just senses the "bus" voltage. If less than about 13v, the control line is off. When the voltage rises above that, it figures the alternator is running and turns on! The delay in switching off (something you'd want anyway) is just a bonus.

And you can't beat the price.

RAD4Runner

Correct, Scope, the "L" circuit (On our first-gen's the "Charge" fuse connects the "L" pin to the negative side of charge fault light. Another misnomer from Toyota. SURPRISE!! LOL

Yup found it.



That's a good solution!