Hella 500 series fog lights. The wiring diagram/instructions is very minimal.
There is a wire from the + terminal to the relay, then a wire from the relay to the switch through the firewall. The switch has a second wire, which is patched into the high beam lead, and a ground. The switch lights up, and my meter shows it has power to the switch.

Then there is a wire from the relay to the aux lights, split, and grounds for each light. There is no power at the aux lights, but high and low beams still work.

I thought maybe my choice of grounds was not good, so I clipped on extra wires and connected them to the - ground strap of the battery. Still no go.

Bad relay out of the box, or am I missing something very obvious?

John, hot and frustrated in Seattle

John;

I'm having trouble understanding your explanation of symptoms and conditions, but in general terms, the working contacts of relay should switch power (from a source like fuseblock or battery) to the loads, when relay is energized (and closes working contacts with a clack).

The working contacts can be isolated (four terminal relay, where two are coil and two are working contacts), or power source for coil and load may be internaly tied together (three terminal relay) in this case the wire going off to the switch gets grounded to chassis to energize coil and transfer power to the output terminal.

I suggest you study the (3 term) relays and their hookup in this wiring diagram: http://www.sw-em.com/122S%20Wiring%20Diagram.jpg

It is unlikely but not impossible I suppose that the relay was bad to start with...does relay clack when you energize it? If not, start there...load (new lights don't even need to be connected for these checks.

Good Hunting!

Thanks for your response. I do not hear a /clack/ when I turn the
switch on, although the indicator light on the switch comes on.
I would assume I had connected wires to the relay incorrectly, but
it is by plugging with a plug which will only go one way.

Sorry my description was unclear. Basically, I have power to the switch,
but no aux lights.

I will try to look at the wiring diagram you referred to, but it seems like a lot--
my diagram is:

-----Relay------Switch-----ground
/ \ |
/ ground spliced to
/ high beam power
to lights (split)
|
ground x 2

Thanks for your response. I do not hear a /clack/ when I turn the
switch on, although the indicator light on the switch comes on.
I would assume I had connected wires to the relay incorrectly, but
it is by plugging with a plug which will only go one way.

Sorry my description was unclear. Basically, I have power to the switch,
but no aux lights.

I will try to look at the wiring diagram you referred to, but it seems like a lot--
my diagram is:

---------Relay------------Switch-----ground
/ \ |
/ ground spliced to high beam power
/
to lights (split)
|
ground x 2

Trying a third time:

John;

That wiring diagram is enough and correct. As I stated in my first post, for a four terminal relay, the coil and working contact are seperate, and the switch is a lighted type which puts voltage across its' lamp (and relay coil) when in the ON position...switch gets its' power from the lighting system (sometimes referred to as being slaved off this system).

Closing switch should put voltage across coil and activate relay with a clack...the fact that indicator light goes ON verifies that you have (slave)power coming from lighting system, but the fact that you hear not clack means that either ground of relay is not connected for some reason, or relay does indeed have an internal problem (again, this is unlikely but I suppose not impossible).

I'd recheck all connections.

Good Hunting