The rally lights on my R53 do not work. Haven't worked since I bought the car -- it took a while for this minor problem to work it's way to the top of the list. As wiring and electronics are not in my wheelhouse, I have a couple of questions.

The behavior: When I turn on the headlights, the rally light switch illuminates. Nothing happens when I push the switch -- the lights don't come on and the indicator on the switch does not light. I have tested this with the high beams on.

What I've tested: The bulbs look good. The fuse is good. The ground to the lights is good. There is continuity from the positive terminal on the lights to the fuse.

I want to test the relay. I have the instructions (as a pdf) and have studied the wiring diagram. I've also watched several videos on how to test relays. Unfortunately, they all work with 4 terminal relays; this one has 9 terminals. I don't understand relays well enough to be certain which to test. Additionally, the terminal numbers on the wiring diagram are small and I can't read some of the. It appears that the leftmost two are 3 and 4, and the fourth one is 2 but I can't make out the others. Not to mention that the diagram shows only 7 terminals.

Any help with how to test the relay is appreciated.

Someone is sure to suggest eliminating the complicated circuitry by installing a simply toggle switch. I prefer not to do that since we plan to relocate in a couple of years. We don't yet know where but the leading contender does vehicle inspections and I don't want to fail because the auxiliary lights are improperly wired. I'd also prefer to keep the installation stock but that's not particularly important.

For those who don't have the wiring diagram, here it is:

 

check the ground for the relay under the hood. They stuck mine near brake reservoir

 

Listen to the relay when you switch the rally lights on and off, it should click audibly. Might be worth getting a second hand one anyway if you can find one cheap

 

Thanks for the replies. The ground for both the relay and the lights tests good -- both are on the same stud under the cowl on the left side.

I haven't heard the relay click when toggling the switch but will double-check that today. I'm also planning to remove the relay and jump the power pins -- the third and fourth pins in the diagram above. I think that will determine whether the problem is under the hood or in the interior wiring/relay.

 

are you operating the driving/rally lights correctly?

the button is not a simple on/off switch ..... the rally lights are tied to headlight operation ... when wired with the factory kit per the instructions.

install instructions p18




p19: Auxiliary driving lamps enhance the "high beam" visibility provided by dual, quad and sixheadlamp
systems and are not a fog light or a substitute for normal headlights. Therefore
these lights will only be operational in conjunction with the high beam lights.

 

Thanks for responding (I've seen your posts in a number of related threads). Yes, I am testing the rally lights with the high beams on.

Diving in a little deeper last night, I think I've figured out that pins 4 and 6 are the control and pins 2 and 8 are the load. So if I jump pins 2 and 8 on the connector, the lights should get voltage and come on, if all wiring from the relay forward is in working order. I hope that's right.

 

Update: Jumping pins 2 and 8 does, in fact, turn on the lights. Well, one of them -- the other has a burned out bulb. So the problem is the relay, the switch, or the wiring inside the car. With the relay in place, there is no click when activating the switch. I suspect that this is because the relay is entirely electronic. I pulled the case off and there is no coil, just connections and a printed circuit board.

BTW, it appears that the numbering of the pins in the diagram is (left to right): 3 4 8 2 6 1 9

Next, I used a test light to check when there is power on pin 4 (from the BCM). As expected, there is power only when the high beams are on. And then I verified that pin 3 is getting power from the connection behind the radio. The switch also gets power from the connection behind the radio.

So it seems that all of the connections are good so I think it must be either the relay or the switch. Any suggestions on how to test to see which is the culprit?

 

One more update: My son's Paceman has rally lights and, as luck would have it, the switch is the same. I tried the switch from his car in mine and it didn't work. I then tried the switch from my car in his and it worked. So my switch is fine. I think I've verified all of the connections to the relay connector as well as the wiring from the relay to the lights, which leaves the relay as the problem. Don't be shy if you see any flaws in my logic.

 

Have you checked the wiring between the switch and the relay? I think that's the only thing you haven't mentioned specifically, but maybe I missed it.

 

Sorry, I should have mentioned that there is continuity between pin 3 on the switch and pin 1 on the relay and between pin 4 on the switch and pin 9 on the relay. Thanks for prompting me to add that to the thread.

 

So the switch is good, you've checked all the grounds, and you've verified that you have power on every pin you're supposed to, if I've read everything correctly.

It sounds like the relay to me then, too.

 

Yeah, I don't think I've missed anything. Thanks for the sanity check. Looks like there is a new (or used?) relay in my immediate future.

 

Is the relay the same in both cars? Could try and have 100% confidence :D

 

I was hopeful that would be the case but, unfortunately, it's not. I found a used relay on eBay listed by an auto shop that used it as a test unit.

 

The rally lights work! It was the relay, which is good because I thought I had eliminated all of the other possibilities. Thanks to all who helped.