96 Mercury Grand Marquis turn signal problem


Old 01-21-02, 05:29 PM
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96 Mercury Grand Marquis turn signal problem

My girlfriend's 96 Mercury Grand Marquis suddenly lost turn signals, brake lights and emergency flashers. While trouble shooting it I discovered that when I turn on the emergency flasher button you get brake lights and turn signals but still no flashers. Fuse box is getting power and no blown fuses, switches function fine etc. Everything I can check seems to point at a module that controls all the flashers, cruise, trans etc. and runs over $270 from the dealer. I've pretty much eliminated everything else. Can anyone tell me if this is something that Ford can electronically (computer diagnose) or reprogram, or is it a replace it only type item. Thanks for any assistance
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Old 01-21-02, 05:41 PM
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If you get no brake lights, you might have a bad stoplight switch.

Check all your bulbs closely. Make sure they are good and of the right type.

If the vehicle has a shift interlock feature (where you have to step on the brake to shift out of park) and that doesn't work as well, that's a brake light switch usually. Happened on my cousin's 93 Taurus.

You might have bad flashers/flasher relays if you have no turn signals or flashers. Could also have a bad ground as well.

Another possibility is a bad multifunction switch in the column. I'm not aware of any "Module" that controls all this. The Grand Marquis is pretty old school.
Old 01-21-02, 05:53 PM
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96 Mercury Grand Marquis turn signals

Well in my first post I did say that there is a module that controls flashers,cruise, trans, brakes lights etc.. I've had it out and held it in my hand and priced it at the dealership.. It does control the functions I discribed earlier.. All bulbs, switches, are good and let me restate that if you turn the emergency flasher switch to on the brake lights and the turn signals will function normally. This system is controlled by a black box (module) buried under the dash. If it was old school I'd already have it fixed
Old 01-22-02, 02:18 PM
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Thumbs down

Another reason not to buy Ford, and stick with simple old GM....yikes, 270 bucks. Poor design. A two dollar flasher lasts 20 years and is a snap to replace.

I have never seen this module, unless you mean the GEM module, but I would still think that something else is at fault. Fordtech is the resident expert on things of FoMoCo origin, and will probably chime in shortly.

I'm still not clear on the symptoms.

You say that when you turn on the flashers, you get turn signals for one thing. The turn signal bulbs and the hazards are one in the same. So, if you have blinking lights when you turn on the hazards they work normally.

Do you get brake lights normally? When you turn on the hazards and step on the brake, what happens?

Check the brake light switch for any breaks/loose connections at te switch. Common Ford problem as their connectors are virtual gum.

I'm leaning to a bad brake light switch, turn signal switch or bad ground somewhere before the module under the dash.

It is likely not reprogrammable from Ford. Replacement item.
Old 01-22-02, 06:11 PM
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The vehicle uses a lighting control module(LCM),similar to a GEM module but just doesn't control as much.From the statements made i'd suspect you have a multifunction switch problem.
A Ford dealer can run codes for the LCM if you want to spend the money for it ,but i'd take a good look at the switch and it's connectors.All you have to do is remove 3 or 4 screws from the steering column shroud,remove the tilt lever(it unscrews),and then the switch is held on with 2 torx/star bits.
Old 01-22-02, 10:12 PM
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Mercury Grand Marquis

Ok Joe and Fordtech, I appreciate the help
I'm strickly a GM man myself and have been turning wrenches since the mid 70's. Sometimes you have to work on a Ford though...no offence Fordtech
When the emergency flasher switch is in the off position there are no brake lights or turn signals. I put a multi-meter to it and it has power to the multifunction switch and to/from the brake light switch. The brake light switch is good. When you turn the emergency flasher switch to on there are no emergency flashers.. but suddenly the turn signals and brake lights function as normal. I know.. it's not supposed to work that way. I checked the grounds already, that's one of the first things I did, and it's good. I will open up the steering column and check the multi function switch. My problem with that is the brake light circuit isn't routed through that switch and it shouldn't affect brake lights if it failed. They all come together in one place.. The LCM as Fordtech called it. A $270 flasher unit Joe. Thanks for the help guys

Old 01-23-02, 10:58 AM
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The turn signal or multifunction switch as it is called is a common Ford failure item.

I'd look there next.
Old 08-18-08, 08:38 PM
Join Date: Aug 2008
Location: midwest, usa
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Wink Turn Signal Problems

I bought a '96 gran marquis. at a funeral I noticed the hazards didn't work. I pushed the button several times. then I noticed my turn signals didn't work or brake lights. Doing resarch online and in this forum I assumed it was module. After reading the attached comments, I went out and pushed hazard button again several times, brake lights and turn signals now work. I assume it must be in the switch mechanism. I can live without hazards but not turns and brake lights.I'll probably have to replace switch mech soon but I don't believe it's the module now.
Thanks for insight.
Old 09-29-09, 06:20 PM
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Thumbs up

If your husband can do the work himself then I would stay away from the stealership as they have steep prices. Looks like thats a good price you found at the boneyard and if your going to trade it in soon anway it looks like a win/win situation to me. Good luck!

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