Subject says it...any idea why? All lights work fine....weird.

The sensor measure the difference in resistance across the sets of bulbs. Changing a bulb with one with slightly different resistance can turn the sensor light on. Also, slight corrosion on the tabs on the bulb sockets where they land on the circuit board, or the circuit board trace can cause a mismatch of resistance.

Try taking very fine, ~200 grit sand paper and sand all the tabs, and with a clean the trace with an eraser. I think its just part of maintaining a 15+ year old car. If it goes out, add a little dielectric grease to the tabs

i have the same problem, only when the headlights or park lights are on
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I need Virgos.....or Coronas....I'm flexible

3rd brake light OK?
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David Hunter

When does it come on? If it's when you brake, don't forget to check the high middle brake light.

Did you replace a bulb recently?

Usual culprits:

-Mismatched bulbs (different brands?)
-Bad grounds
-Bad bulb sensor (not uncommon)

-Ryan
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Athens, Ohio
1987 245 DL 314k, Dog-mobile
1990 245 DL 134k M47, E-codes, GT Sway Bars, GT Braces
1991 745 GL 300k, Regina, 23/21mm Turbo Sway Bars
Buckeye Volvo Club

Been chasing that one around since I bought the 780 .... we have traced the problem down to related to the cruise control ... believe it or not . The previous owner solved the problem by removing the bulb from the dash .... I still haven't solved the cruise problem I have either ... so far we have substituted 3 speedo heads, 3 cruise modules and 3 steering column switches with known good units to no avail ... now what the Cruise has to do with the doggone light out indicator light is totally beyond me .... IF I have lights off ... the light out warning only shows during braking ... if lights are on it shows all the time ... anyone have any ideas ? Or do I just remove the dang bulb again ?? Anyone who has any suggestions about my Cruise control ... all suggestions are welcomed .

Brett
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Brett Sutherland & the 1.5 million mile 122 CANADIAN --- WINDSOR, Nova Scotia the birthplace of HOCKEY www.ecvintagevolvo.com

3rd brake light is OK.

It used to come on only when I pressed on the brake. Sometimes it would go out, sometimes it would stay on, but eventually it would go out. Then I did replace a bulb, and it now stays constant.

I will take that bulb out and get the correct bulb, as it appears not to be the right type.

I will reply when I find out.