LED under the hood lights on Timer???? Is this possible???

Hi Guys,

I recently installed LED lights under my hood. (Probably one of the coolest mods I have done for under $20) I have them wired to a pole switch which breaks contact with the ground when the hood is closed and completes the circuit when the hood is opened. I would like them to turn off after a set amount of time, ~10 mins, that way if I have the hood up but don't need them I will not drain my battery. I would want to simply have to push the pole switch so that the circuit is broken and then let it go, complete the circuit again, to start the timer over.

I've spent countless hours looking on the internet and on TW but haven't found out if this is possible. While I know a bit about electrical stuff I am no expert and if this is a stupid question I apologize.


Thanks,

Kevin

 

I've used this circuit before but I lost all my calculations for timer ratio between R1/C1.

 

Well you could use a "timer relay". Your current circuit would pull in the relay's coil and the relay will stay engaged for xx seconds after the hood is closed.
The timer usually had a dial you can adjust. The wiring for the lights themselves would go through the relay contacts and controlled by the relay.

 

I did the same mod & am considering adding a simple switch to the works in case I don't need the light but need the hood open for an extended period. Seems like the most simple solution to the issue.

 

This was my first thought and I can also pull the fuse pretty quickly. My thought is for when I take it in for service, I don't want to have to explain to every tech how to switch it off. I guess I'll just have to remember to switch it off before I take it in. Just seemed like there should be a easy way to add a timer.

 

Jarrod,

Thanks so much for the help. Sadly this is over my head. I understand bits of it but definitely don't think I could build it.

 

Google "12V light delay module". Check the New Egg offering. It's not weather proof so you'll need to shelter it. You can program it from 0-999 seconds (16.65 minutes max) and it's very inexpensive. Let me know if it works. The other thing that crossed my mind is that should your LED light be very low draw, it would not drain your battery enough to keep your engine from starting. I say this 'cause I've left the dome light on twice overnight. Engine started fine.

 

If you don't want to change the time frame (~10 min) the "Toyota Highlander Mirror Switch Part No. 84871-48030 " might fill your need. It's a timer switch, fits the blanks in the dash, and could run led's directly w/o a relay. The disadvantage is that it's a fixed time interval for shutting of a rear window defogger relay. But it would be an easy install in the dash if you want to pull wires. Not weather proof though so under-hood install would need protection.

 

That would require you activating the hood lights every time with that switch though. Ours are both installed with the ground on a hood pin so they just automatically come on on their own. Wiring this switch would require you to activate the switch manually each time negating the automatic feature of our install.

 

I may have an extra 555 timer laying around in my component box. If I have one I could build you one if you're not able to find a timer circuit somewhere.

Other users have pointed out a timed relay which will most certainly suffice and they are readily available but I'm too much of a DIYer to let that happen on my truck

Hope you get it figured out sir!

 

If you have a reed switch that's configurable for NO/NC you could potentially wire it to use the OE switch and the switch in the hood to run it. Not the most efficient way but it could most certainly be done.

 

You could put all your extra accessories on a "valet switch".

 

tap them into the dome lights.

"omg ecu load blah blah blah"

they'll be fine... you'll never forget them, and they will be protected by the trucks logic to shut them off to never drain your battery. they will stay on as long as your door is open. its how i ran my bed lights. simple to do. keep it simple.

 

I'll have mine tied into the Dome with my door lights on a 3 Position switch in the cab.
{Switch}
- Constant On
- Off
- Normal Dome function

 

How long do you plan on having the hood open? The LED lights shouldn't draw that much off of the battery unless you are leaving it on for days. Just install a second switch where you could turn them off when you don't want them on. If they are on a timer they could turn off when you are in the middle of working on something and need them

 

However; the hood latch under the drivers left knee has to be flipped to open the hood; how hard is it to also push a switch right above it?

Also if the led's are bad-ass bright, w/o the underhood switch you could flip them on for hood-down road lighting...

 

It has nothing to do with difficulty. It's not that hard to hold a flashlight either but misses the point entirely.