Gemini67

I am trying to diagnose a problem with my headlights. I'm in Canada so I have Daytime Running Lights (DRL) on my Max. The problem is that the DRLs light up okay (they use a lower light setting on the high beam bulb), but then when I turn on the headlights and the high beams the passenger light goes out. I have replaced the passenger side high beam bulb with a brand new bulb, no difference.

I looked at the service manual and it suggests that the headlamp relay may be a problem. It refers to a RH and a LH relay ,which i assume is right hand(passenger) and left hand(driver).

Can any tech tell me if there is a difference between the two, they have the same numbers printed on them, but does that make them the same? (I know DUMB question.. I don't want create more problems)

If they are the identical part, I want to swap them from side to side to see if the problem follows the relay.

Thanks.

Gemini67

Bump?? Anyone have an idea?

Thanks

Gemini67

Okay, I dove in and switched the relays, the problem still remains on the passenger side, so it's not the relay. Somebody else suggested the DRL module, anybody know where the DRL module is located?

Thanks

5thgenmaxima

iTrader: (1)

You need to find out if it's the relay side of the relay or the head lights side..
Are the left and right relays in the same relax box??
If so put your hand on both of them. When the left one clicks the right one should as well.

(You may need a friend to toggle the ignition and/or light switch on/off.)

Gemini67

Well, I have swapped the relays and the problem STAYS on the passenger side. I'm guessing it's NOT the relay but something else, like the DRL module as someone else has suggested in another post.

I'm still looking for the DRL module.

5thgenmaxima

iTrader: (1)

The relay has two circuits. The relay side and the light circuit side. When the relay activates it pulls completes a circuit for power to go to the lights. The easiest way find out if your problem is in the relay circuit or the part going to the lights is to listen to it to see if it clicks. If it clicks then that means the driver is activating the relay so your problem is the light side. If it doesn't click then that means the problem is the wire from the power or driver to the relay (On the relay side)

Gemini67

So, are you saying that the relays are probably good, but the problem exists between either the headlights and the relay ...OR... between the relay and the headlight switch.

Or did I miss it entirely??

5thgenmaxima

iTrader: (1)

According to you when you switched them the problem stayed on the same side. The relay is probably good. I'm getting ready to leave work, I'll explain in more detail tonight once I get the kid to sleep.

5thgenmaxima

iTrader: (1)

OK, kinda short and sweet.
As you can see in the attempted drawing of the relay there is two sets of wires.
one set is going into the relay thru a set of coils and out the other end to a low side driver.
The other set goes goes to the load the relay circuit is ultimately controlling.

first keep in mind---You can put power to anything, without a ground it won't work.

To begin look at the pic of the relay to the left of the drawing.
You can see the "wire" inside the relay is going to a circuit which leads to nothing. "example wire"
On the right pic you can see the wire goes to the light.

If you would have someone turn the lights on/off while you had your hand on the relay you would feel and hear a clicking noise. What happens is that when you turn your lights on your allowing the coil side of the relay to ground and this completes a circuit on the coil side of the relay.
What this does is energize the coil inside the relay and it takes that "wire" that usually goes to the example wire prong and pulls the "wire" over to the light circuit prong which allows power to flow to your light bulb.

Therefore if the relay "clicks" when you turn your lights on then you know that the circuit on the coil side of the relay is good allowing the coil to energize in turn completing the circuit for your lights to turn on and this narrows your problem down to the light side of the circuit..
If the relay doesn't "click" then that means you have a problem on the coil side of your relay.

Now I'm sure your asking yourself why would they use a relay? Why wouldn't they just put the switch on the light circuit and save themselves the money/hassle of doing this?
Answer = The light demands a higher amount of ampreage to fully light than the coil takes to energize. Therefore is the switch was on the same circuit as the bulb it would have a higher tendancy to burn out since more amps would be flowing thru it...

NYPD-Arnold

iTrader: (8)

Check your grounds. I had this very same issue with one of my 03 headlights, and it turned out that it wasn't grounded right.

5thgenmaxima

iTrader: (1)

Yea it could def be a ground. I automatically assumed a visual inspection had already been performed.. Guess I should have said that first for the newbie, lol.

NewLoveI30

Sorry to sort of jack the thread, but anyone know if U.S. cars are wired for this already?

I already have the fogs wired to come on with the city lights, but I'd also like to run the highbeams at say 35w when the city lights are on. Any of you electrical gurus know how I would wire to do this?

5thgenmaxima

iTrader: (1)

I'm a bit confused. You have your fogs sliced into your lowbeams and are wanting to also slice them into your highbeams? Unless your running two loads in series it won't matter how many watts. Just run 12V and the bulb take care of the rest. (Unless your running both bulbs in series. I.E. on the same circuit using the same electrical path.)

If your slicing into your lowbeams and high beams and tying both of them into your fogs then your highbeams wil come on everytime you turn your lows on.