headlight problem

Asked by Dec 26, 2012 at 01:24 AM about the 1990 Mercury Grand Marquis 4 Dr LS Sedan

Question type: Maintenance & Repair

1990 (mfg date 11/89) Mercury Grand Marquis, 5L, MFI, loaded

Cut to the chase:  what is the correct multi-switch (dimmer) for this vehicle?  O-Reilly's says (and gave me) a BWD #S3217.  I think it is wrong.  Now the story:

About a year ago the brights began going out (all lights out).  Switching to dims brought them back.  Thinking it was the multi-switch, I bought another.  A previous vehicle ('79 Toro) had a similar problem that turned out to be the multi-switch partially melting.  As it was near the end of winter and I had little time, I put the switch in the trunk and drove on dims.  Friday, on the way home for Christmas weekend (of course) the lights started going off entirely.  Fiddling with multi-switch got me home.  I could hear a clicking behind the dash as they turned on and off.  I have since read that the problem may be the headlight switch (WAH).  The wah is because I replaced the multi-switch and disassembled the old one to diagnose problem.  All I found was some carbon blacking on the contacts.  This switch is built much better than the Toro switch.  I see no evidence of plastic melting.

Anyway, problem now is that I now have daytime running lights (didn't before), and the battery drains overnight.  Disconnecting the battery and putting an ammeter in series, I get a 1 amp drain with doors shut, no key in ignition, trunk shut, and hood bulb unplugged.  Oh yeah, when I say I have daytime running lights, it doesn't matter whether the headlight switch is pushed in or pulled out (yes, old style) the lights come on as soon as the key is turned and will not turn off (key out, waited over a minute) until the battery is disconnected (stay off after battery re-connected until key turned on).  The only thing I have done during this project has been to remove the old switch and replace it with the new.

I suspect I was given the wrong switch (ya think).  I am thinking about getting a battery cutout switch tomorrow so I can drive to work (30 miles each way) and not have battery drain down while at work, but am concerned that the incorrect switch may cause other problems.

HELP!!!

Really, any assistance will be greatly appreciated.

Roy

1 Answer

6,945

Make sure that they gave you the switch with the headlight delay. There are two switches. One for cars with headlight delay, one without. It seems like you got the one without, that's why the lights are not going off. Go back to reily's and have them double check it for you. Most of these autoparts stores nowadays have kids working there that don't know didly-squat about cars, especially one that's probably as old or older than they are. Kenny/MrBlueOval

Your Answer

Mercury Grand Marquis Experts

  • #1
    Tracy Hooks
    Reputation
    5,780
  • #2
    kbro
    Reputation
    2,150
  • #3
    Js08016
    Reputation
    1,880
View All

Related Models For Sale

Used Lincoln Town Car
41 Great Deals out of 1,744 listings starting at $1,000
Used Ford Crown Victoria
5 Great Deals out of 1,172 listings starting at $1,496
Used Ford F-150
2,485 Great Deals out of 193,493 listings starting at $799
Used Ford Mustang
588 Great Deals out of 36,170 listings starting at $1,800
Used Cadillac DeVille
1,580 listings starting at $2,995
Used Chevrolet Caprice
191 listings starting at $9,995
Used Ford Taurus
185 Great Deals out of 15,819 listings starting at $1,850
Used Lincoln Continental
16 Great Deals out of 3,910 listings starting at $35,942
Used Chevrolet Camaro
397 Great Deals out of 30,576 listings starting at $2,495

Used Cars For Sale

2011 Mercury Grand Marquis For Sale
24 listings starting at $5,450
2010 Mercury Grand Marquis For Sale
4 Great Deals out of 92 listings starting at $4,995
2009 Mercury Grand Marquis For Sale
6 Great Deals out of 81 listings starting at $2,799
2008 Mercury Grand Marquis For Sale
9 Great Deals out of 152 listings starting at $2,790
2007 Mercury Grand Marquis For Sale
8 Great Deals out of 125 listings starting at $1,995

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.