Fog Light Problem

[Dragonlady]

Hi,

We have just had the NSX serviced and the garage has rung to say that there is a problem with the Fog Light. Apparently the light came on and off intermittently, and then just stayed off. They have checked the bulb and wiring and have said that they appear ok. Has anyone had anything similiar?

Need to resolve the problem before her MOT in 4 weeks :(

Cheers

Sharon

[JQD84983]

When they have said they have checked the wiring did that include the switch or relay that triggers the light.

I am no expert on the NSX wiring (Sudesh and Kaz will probably be able to confirm). If there is no short circuit in the wiring it can only be the switching contacts.

Hope this helps

Regards

John

[Kaz-kzukNA1]

Hi,Sharon.

There was nothing mentioned on whether both R & L fog lights or just one side was not working but I presume both sides were not working as your garage checked at least one of the bulb and found it was fine.


The fog light circuit consists of the followings;

* 15A Fuse #41 inside the Main Relay Box under the bonnet. It’s the pentagonal shape box and the location of the fuse is on the cover sticker (if it is still there). The fuse number could be different for UK model.
* The Fog light Sw at the centre console
* The Fog Light Relay under the bonnet
* The R & L Fog Light unit
* GND G202 at the right side under the bonnet
* The wiring

As it sounded like intermittent issue while the car was at your garage, it is very unlikely but please check the 15A #41 fuse.

Did you remove the centre console or work on the nearby area recently?
Do you get green light at the fog light sw when you press it?
While keeping the main light sw (the one close to the indicator lever) in OFF position, if you press the fog light sw, does your front marker lights as well as the small tail lights come on? If so, your fog light sw would be fine.

If you have the bench power supply, you can easily check the fog light unit by applying the 12V directly at the 2pin connector.
If you are careful enough, you can apply the battery power to the 2pin connector for a quick check.

Fog light relay can be checked with ease as it is a N.O. type and there are lots of same model relays nearby so you can swap it with known good one.

If it is wiring related, it could take a while to pin point the damaged area....

Hope these will help you in diagnosing the issue.

Regards,
Kaz

[Dragonlady]

While keeping the main light sw (the one close to the indicator lever) in OFF position, if you press the fog light sw, does your front marker lights as well as the small tail lights come on? If so, your fog light sw would be fine.



Hi Kaz,

Thanks for the quick response.

Our car is a 2002 so I'm not sure, but by front marker lights, do you mean front fogs/driving lights?

After I got the car back home I thought that I would try the fog light myself. After switching on the main lights I depressed the fog light switch and the little green light came on with the fog lamp. By the time I had walked back to turn it off the green light had gone out and the fog light was off as well. I tried the switch a few more times but the fog light would not work.

Does this sound more like a dodgey switch or could it be the relay playing up?

Thanks Ian

[JQD84983]

Does this sound more like a dodgey switch or could it be the relay playing up?



Sounds Like relay to me. Am assuming that the relay switches the fog lights through 1 pair of contacts and the light on the switch through a second set. Therefore getting neither would point to the relay IMHO

Regards

John

[Kaz-kzukNA1]

Our car is a 2002 ........

Thanks Ian
Ah... I see. Forget about most of the points I wrote above.
You don't have Front Fog lights and instead, you were talking about the Rear Fog light.

The concept of checking procedure is the same as in my post above however, the power source to the relay is different.

I'm in the middle of something (working today) so will get back to you later.

Regards,
Kaz

[Dragonlady]

Ah... I see. Forget about most of the points I wrote above.
You don't have Front Fog lights and instead, you were talking about the Rear Fog light.

The concept of checking procedure is the same as in my post above however, the power source to the relay is different.

I'm in the middle of something (working today) so will get back to you later.

Regards,
Kaz

Thank you

Ian

[Kaz-kzukNA1]

So, now it’s the Rear Fog circuit.

It consists of the followings;
* The rear fog light relay under the bonnet
* The rear fog light sw
* The rear fog light unit [Edit: socket]
* GND G401/403 for the sw contact and ORANGE indicator light at the rear fog sw
* GND G551 for the rear fog light unit [Edit: socket]
* The wiring

As you know, the rear fog light only works when the headlight is On.
This is achieved by supplying the power to the upper side of the relay coil through the headlight On circuit.
The lower side is connected to the GND G401/403 through the rear fog light sw.

The upper side of the relay sw is connected to the power from the marker (position)/headlight On circuit.
The lower side is connected to the GND G401/403 through the ORANGE indicator at the rear fog light sw AND to the GND G551 through the rear fog light unit. [Edit: Hence, it will switch on the Orange indicator AND the rear fog light at the same time.]


I believe your garage didn’t notice any issues with your headlight system therefore, the power source to the relay coil and relay sw seemed to be fine.

There are lots of same one used nearby the rear fog light relay so it is easy to swap it with the known good one.

From time to time, I noticed loose connectors under the switch modules at the centre console.
Please check the connection by removing the switch block. You can pop them out without removing the centre console if you can put your fingers from the small gap around the parking brake lever.

You can easily check the switched power at the rear fog light bulb socket with the multi meter.
Please look for any corrosion [Edit: at the socket] caused by the condensation inside your boot.
Quite often, the condensation at the tail light assys is caused by the humid warm/hot air passing through the weaken foam seal behind the assys and this moisture can cause corrosion at the base of light bulb socket.

If you know the pin out of the relay, you can apply 12V or GND to the specific terminals to check each components and wiring.

Hope you will find the cause of issue.

Kaz

[nigel]

Maybe you should remove the entire rear foglight system and send it to me and that will cure that. That's the next thing on my "can't get here in the States" list.
As most know i've nearly all my entire headlight washer system done and now it's time to get a RFLS and that will be two things that only i've got from a UK car here in the states.

Cheers
nigel

[Dragonlady]

Though I would try and fix or find the offending part today.
Does anybody or Kaz know which is the rear fog relay under the bonnet please? They does not seem to be any information on what relay does what in the manual.

Thanks Ian