Even USA spec Volvos have rear fog lights. That switch next to your head light switch is for the rear fog. There is only one bulb installed at the factory on the left side. It's the same as a brake light bulb. If you want to put one on the right hand side, just break off the punchout on the right tail light housing and insert a bulb. The wiring is already there.

Wiring for the front fog lights is already in the car, if you want to add them. But all fog lights ONLY work when the head lights are ON. Daytime running lights do not count.

As an old Army brat, I wish I could be over there and checking out what the real top end of my 850T really is. Watch out, the car on the right has the right of way, ALL of the time.

Klaus
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98 V70Rawd(101Kmi), 95 854T(85K mi), 88 245(165K mi)

Your V70 should already be equipped with a rear fog light if it was built for European or Canadian export. It's incorporated into the rear tail light lens. The switch should be beside the front fog light switch. It is essentially the same candle power as the brake light. Check your service manual for its location, switch etc. If it was not installed, then I'm sure the Volvo dealer will be able to obtain it for you. I'm 100% sure the wires are already installed. Good luck.
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Cam a.k.a. CVOLVO.COM