[aintsheswede]

My right rear fog light is not working. Changed the bulb, but was not the problem (on inspection, the existing bulb looked okay, but I was hoping for the simple fix). Tail light and all other lights work, just not the fog on that side. Anyone have this problem, or ideas on where/what to check for before going to the dealer? The wiring seemed okay, but I didn't check too close, as was going for the bulb replacement first.

Is it correct that the socket in the tailight housing only has one contact, as it is a dual filament bulb with 2 positive contacts on it?

And finally, has anyone noticed the owners manual (MY 06) seems to be a bit confused as to the location of the rear fog lights in the bulb replacement instructions?

Thanks.

 

[robtr8]

Re: Rear Fog light not working (aintsheswede)

From wikipedia "Automotive Lighting"

Rear fog lamps

In Europe and other countries adhering to ECE Regulation 48, vehicles must be equipped with one or two bright red "rear fog lamps" (or "fog taillamps"), which serve as high-intensity rear position lamps to be energised by the driver in conditions of poor visibility to enhance vehicle conspicuity from the rear. The allowable range of intensity for a rear fog lamp is 150 to 300 candelas, which is within the range of a U.S. brake lamp. For this reason, many European vehicles imported to the United States have their rear fog lamps wired as brake lamps, since their European-specification brake lamps may not be sufficiently intense to comply with U.S. regulations, and in North America rear fog lamps are not required equipment. However, they are permitted, and are found almost exclusively on European-brand vehicles in North America - Audi, Jaguar, Mercedes, MINI, Range Rover, Saab and Volvo provide functional rear fog lights on their North American models. The final generation Oldsmobile Aurora also had dual rear fog lights installed in the rear bumper as standard equipment.

Most jurisdictions permit rear fog lamps to be installed either singly or in pairs. If a single rear fog is fitted, most jurisdictions require it to be located at or to the driver's side of the vehicle's centreline - whichever side is the prevailing driver's side in the country in which the vehicle is registered. This is to maximise the sight line of following drivers to the rear fog lamp. If two rear fog lamps are fitted, they must be symmetrical with respect to the vehicle's centreline. Proponents of twin rear fog lamps say two lamps provide vehicle distance information not available from a single lamp. Proponents of the single rear fog lamp say dual rear fog lamps closely mimic the appearance of illuminated brake lamps (which are mandatorily installed in pairs), reducing the conspicuity of the brake lamps' message when the rear fogs are activated. To provide some safeguard against rear fog lamps' masking of brake lamps, ECE R48 requires a separation of at least 10 cm between the closest illuminated edges of any brake lamp and any rear fog lamp.

Modified by robtr8 at 11:51 AM 2-22-2009

Modified by robtr8 at 11:58 AM 2-22-2009

 

[Joesid]

Re: Rear Fog light not working (robtr8)

There seems to be a bit of confusion due to the location of the rear fog light. In the MY '03 it is built into the main tail lamp (parking lamp below turn/reverse lamps). I just looked at the MY '06 online manual and it seems as if Volvo moved the fog lamp down to the marker lamp on the bumper?

I understand changing the fog lamp location with the '07+ refresh.... but changing the location between the '03-'06 years seems odd to me. Oh well.

 

[JimJa43]

Re: Rear Fog light not working (Joesid)

Up front I'll admit I'm guessing here, but I don't believe the U.S. DOT has a regulation about rear fog lights... yes/no? Sort of like the side marker lights on European vehicles - okay to have them but not a requirement in the U.S.

I've only seen them on European vehicles - at least I don't recall of ever seeing one on any U.S. or Asian vehicle.

And I've only seen them on the left rear. In my '08 it's in the reflector lens in the bumper. I owned an Audi some time ago and it was in the tail lamp, also on the left. Probably only on the right in vehicles with right hand drive.

 

[robtr8]

Re: Rear Fog light not working (JimJa43)

I was writing in shorthand. I have revised my post. May not be DOT but the point was stop trying to fix what ain't broke. My '90 90, '90 CQ, '92 100, '95 S6, '00 A6 2.7T, and now '06 XC90 have all had left only rear fogs.

 

[aintsheswede]

Re: Rear Fog light not working (robtr8)

Thank you robtr8 for the indepth reply. That answers all my questions. It obviously was not wired for the foglight on the right. I was trying to think about the logic of only having one on the left and not coming up with a good answer. I would be a proponnet of having both, as I would think it may be a bit confusing for a following driver, wondering if you had a brakelight out and were just riding the pedal. Having lived a great many years in the central valley of CA, with periods of fog so thick you literally could not see more than a car length, I think they area great safety feature.

And I also wonder how many law enforcement officers actually realize it is normal to have just the left and not just a bulb out!

No matter, mystery solved. And I appreciate all the responses. At least I learned how to take the tail light assembly out.

As far as the owners manual, it looks like they changed it there before actually changing the location in the vehicle. Because in my MY06 they are definitely the combo tail light bulb, not the bumper location.
Thanks again.

 

[robtr8]

Re: Rear Fog light not working (aintsheswede)

No worries, I originally thought the one side only thing was European and they just didn't bother to change it when they sent the cars over. In researching my post today I learned Europe was two lights and US only one. Thats why I assumed it was a stupid DOT rule that made them modify the cars. Cibie Z beams were only legal for "off road use" because of DOT even though they were far superior lights, for their time.

 

[lauri]

Re: Rear Fog light not working (robtr8)

Quote, originally posted by robtr8 »

In researching my post today I learned Europe was two lights and US only one.

You can have one or two in Europe. Rear fog lights that is.

 

[JDN34]

Re: Rear Fog light not working (lauri)

To confuse the topic even more. On my Audi, 2000~03 have single driver-side rear fogs. 2004~5 is dual rear fogs at the exact location (the right side blub was just simply not installed for the older MY)

 

[choud]

Re: Rear Fog light not working (lauri)

Quote, originally posted by lauri »

You can have one or two in Europe. Rear fog lights that is.

It's generally recommended by automotive organizations only to have one, situated in the driver's side, as not to confuse it with the brake lights.
Reason for having space for them in both sides could be because of RHD countries.

 

[lauri]

Re: Rear Fog light not working (choud)

Quote, originally posted by choud »

It's generally recommended by automotive organizations only to have one, situated in the driver's side, as not to confuse it with the brake lights. Reason for having space for them in both sides could be because of RHD countries.

Yep, but I once had -85 Citroen BX which had fog lights on both sides. From factory.

 

[Parts @ Boston Volvo]

Re: Rear Fog light not working (aintsheswede)

Volvo went from two rear fog lights to one on the drivers side starting with model year 1991.

John