By Alex Schubow (Alex) on Tuesday, August 28, 2001 - 04:19 pm: Edit

I plan to splice into my brights wiring so my Hellas will turn on with the brights, but maintain the hella switch functionality at other times. In order to do this, I have to wire a diode in line with the splice, or the brights will turn on every time I turn on the hellas due to feedback into the brights circuit.

I looked at Radio Shack, all their options seem too puny. Painless wiring doesn't seem to have anything either.

Any ideas where an animal like this could be sourced?

TIA, Alex

By herky on Tuesday, August 28, 2001 - 04:58 pm: Edit

A good mobile install shop should be able to provide you with a decent diode, got to one that does alot of alarms. They should have one with the proper value.

By Ali on Wednesday, August 29, 2001 - 06:24 am: Edit

Alex,

Is it not possible to do this using a relay? Tap off of the bright circuit to activate the relay. Then have this relay power up your current circuitry. This way your power sources are separate.

By David Dryden (David914) on Wednesday, August 29, 2001 - 01:18 pm: Edit

You should already be using a relay to power your Hellas. You will need to isolate the brights from the Hellas, though. All you need to do is install a diode from your brights to the positive side of your relay coil along with the feed from your dash switch (assuming you're using a positive feed from your dash switch). The relay doesn't use much current (about 30-50 milliamps usually) so any average diode will do. I'd use a 1N4004. It'll handle 1 amp easily and has a fairly high PIV (peak inverse voltage). Good luck!

David

By Alex Schubow (Alex) on Wednesday, August 29, 2001 - 02:33 pm: Edit

I probably will wind up using another relay. The hellas are each wired to their own 30 amp relay, using the stock foglight wiring to activate the relays. I just wanted to use a diode because it is simpler. I will stop by a car audio shop tomorrow, and if they don't have have a suitable diode, I'll just add onther relay, which will be activated by the brights, and will in turn activate the hella switch circuit.

What's a 1N4004? I was hoping to find something that would use crimp-on spade terminals for simplicity's sake.

Alex

By Discosaurus (Discosaurus) on Thursday, August 30, 2001 - 05:12 am: Edit

I would need to look at my wiring diagram, but I believe it's all a matter of WHERE the foglight relays get their power from. In a stock Disco, the factory fog relay is supplied with power ONLY when the headlights are in dim. By changing this feed to another location, you can have the foglight relays powered up when in high beam or both high and low beam.

I don't think it's too difficult to get those relays to do whatever you want without resorting to even more solid-state electronics.

keith
discosaurus

By Alex Schubow (Alex) on Thursday, August 30, 2001 - 05:59 am: Edit

OK OK, let me start from the beginning.

This is how my system is currently set up.

I modified the stock foglight switch to get power from the parking lights. The switch feeds three 30 amp relays, each one is connected to a hella 4000. The switch will turn on the Hellas if the parking lights, or low beams, or high beams are turned on.

What I want to do is have the Hellas turn on when I flick on the brights, even if the hella switch is off. The switch will still be able to toggle the Hellas if the parking lights or low beams are on, but if the brights are on, the Hellas will turn on regardless of the Hella switch's position.

So I'm going to tap into the brights circuit, with an in-line diode, to power up the Hella switch circuit (after the switch), which will in turn power the Hella relays and turn on the Hellas. When the brights are turned off (if the Hella switch is off) the Heallas will turn off also. I will use this for driving on country roads at night so I can toggle all my bright lights with a flick of the stalk, instead of the stalk and another switch.

Alternatively, if I can't find a suitable diode, I will wire a fourth relay in the system. The relay will be powered up by the brights circuit, and in turn power up the Hella switch circuit as described above. Either of these methods will prevent feeding back of current into the brights circuit when the Hella switch is on (otherwise, the brights would turn on whenever the hella switch was on, regardless of the brights switch position).

Phew.

Alex

By Carl E. Cedeholm (Cederholm) on Thursday, August 30, 2001 - 06:31 am: Edit

FYI,
You might already now this but Radio Shack online (radioshack.com) has a much wider selection of electronics than the stores.
If your near Boston, there's a place called U Do It electronics...they'd have it.
Carl

By Tom Proctor on Thursday, August 30, 2001 - 06:49 am: Edit

Alex,

Why not just add a second *feed* switch (along the lines of Keith's suggestion)? A simple toggle switch that could change the feed to the fog switch from parking lights to high beam. When you drive the country roads, flick the toggle to high beam, then you have single stalk control. But with the toggle on parking light feed, you're back to the your current system.

That said, your Diode system does seem novel, and would give you *seamless* operations results (i.e. no extra switch to throw).

Tom P.
BTW, your country road analogy is exactly why my driving lights are fed from the high beam. Flip the switch and forget about it.

By Alex Schubow (Alex) on Thursday, August 30, 2001 - 08:37 am: Edit

Another relay will give me the same thing, but with more wires I'm stopping by the car audio shop today after work, if they don't have it, its off to Pep boys for a $5 relay. Watch out anyone who cuts me off in traffic! Nothing like using 400W worth of lights in anger!

Alex

By Alex Schubow (Alex) on Thursday, August 30, 2001 - 03:21 pm: Edit

Picked up a 3 amp diode for a dollar at the car audio shop, soldered it in line between the brights and the hella switch, and it works marvelously. cheap, easy, simple.

Thanks for your suggestions.

Alex

By David Dryden (David914) on Friday, September 07, 2001 - 06:42 am: Edit

Been away for a few days. Glad to hear the diode worked. BTW, a 1N4004 is a type of diode, like a 235/60-16 is a type of tire. It's a size/rating thing. My point was that you shouldn't need anything real heavy-duty since you just need enough current to fire the relay (which draws much less than 1 amp). Glad to hear everything turned out OK!

David