I have two sets of driving lights wired up: Hella FF100s and Hella 500s. I've had the FF100s wired up for awhile, and they work fine (i.e., the switch is only active when the high beams are on, and the lights automatically go off when the high beams are switched off). The switch itself is only supposed to illuminate (red or green) when the high beams are on.

I recently added the 500s on their own relay, and I just wired the new relay so that it triggers from the old relay.

The lights still work more or less as expected, except that sometimes, they won't turn off when I turn off the high beams. If I cycle high-low again, then they will usually turn off. The switch lights remain on as well. It seems like one or both of the relays is "sticking" closed or something.

Any ideas?

relay is sticking or faulty like you said, just replace the relay.

relay is sticking or faulty like you said, just replace the relay.

That would be the obvious answer, but that either means that:
a) The brand-new relay I installed with the new lights is faulty; or,
b) The relay that was already in there and working fine coincidentally became faulty right when I installed the second relay.

I find either scenario unlikely . . .

We need to know where you tied into the high beam light system to control the new relays. Wherever it is, it sounds like the relay that controls the high beams is possibly sticking or something else isn't switching as it should.

We need to know where you tied into the high beam light system to control the new relays. Wherever it is, it sounds like the relay that controls the high beams is possibly sticking or something else isn't switching as it should.

I'm 99% that the original setup was wired exactly according to Hella's diagram - but I'll check tonight and make sure. IIRC, there's a vampire tap off the high-beam harness:
http://www.rallylights.com/useful_info/auxiliary_lamp_wiring.htm
The new relay has its own ground and battery connections, and just taps pin 86 from the other relay for switching.

What's also weird is that even before I added the new relay and lights, sometimes the switch light would stay on (albeit faintly) when I switched to low beams, and if I cycled the switch a few times, the light would get dimmer until it disappeared completely - even though the driving lights themselves wouldn't come on. It's almost as if there's residual charge in the system somewhere, but I don't know how that could happen.

I looked at the link you provided. Did you notice the note at the bottom talking about the ground for the light switch and the need to have it reversed from the normal way since the lighting uses a switched ground system instead of switched power? Have you wired it for the switched ground method? It would still help me to know exactly where you tied in the wire for the new switches for the relay control.

To make it clear for me when you talk about the light switch is staying on I assume you are talking about the switch for the first set of Hellas. Is that correct? I assume all the original lighting and switches are working as they should be, correct?

I looked at the link you provided. Did you notice the note at the bottom talking about the ground for the light switch and the need to have it reversed from the normal way since the lighting uses a switched ground system instead of switched power? Have you wired it for the switched ground method? It would still help me to know exactly where you tied in the wire for the new switches for the relay control.

To make it clear for me when you talk about the light switch is staying on I assume you are talking about the switch for the first set of Hellas. Is that correct? I assume all the original lighting and switches are working as they should be, correct?

I will have to check my wiring and confirm, but I'm pretty sure that it is configured correctly for switched ground.

As far as the light switch, it's the switch for the first set of Hellas - but it now operates both lights (so the switch turns off/on both the 100s and the 500s). I didn't add an additional switch for the new lights.

Thanks for the clarification. So this means you supplied power to the new switch and seriesed relay coil and then tied the other end of the circuit to the systems switched ground.

I suspect that you are getting some back feed somehow on this due to the lights in the switch. If that is so one quick thing you might try to fix this is putting in a isolation diode in the line to the orignal system connection. We should be able to find a point to tie to also in the original system so it isn't needed.

Thanks - I'll post up a more detailed wiring diagram/description when I get home and have a chance to look over things.

You're welcome for the help.

The way it looks to me right now I think you may have the lead tied to the dimmer/passing switch. Pin 7 has a red/green wire tied to it and it is switched to ground when the highs are on. This is where I would expect the lead to be tied to at least.

Update:

Things got weirder: the switch will periodically stop illuminating when the high beams come on, and I thought that the relay had failed totally. Then I tried it again last night and it was back to "normal". I'm pretty sure one of the relays must be bad, but if they are working intermittently, how am I going to figure out which one is bad?

I assume all I have to do is apply 12V across the switching terminals and listen for the "click" . . .

Sorry I still haven't gotten around to confirming the wiring setup yet . . . I need a block of time to work on this. :unamused: