Stop Lights / Turn Signal Inop

allenmarks

Registered
Dealing with a 1996 Mark VIII

Symptom: Turn signals and stop lamps are all inoperative. The 5th stop lamp on the rear deck works normally. Tail lights function normally when headlights are on.

Checked all fuses, wire bundles, connectors (I could locate), etc. Ordered books, however everything is back ordered.

Any suggestion where to go? My skill level is good to moderate.

Thanks,

Dark in Flordia.......:(
 
RE: Stop Lights / Turn Signal Inop

Double-check the wiring harness under the carpet on the left side of the trunk. A number of people here have had similar problems and found that insulation on the wires in that location have worn through or broken, causing either intermittent shorts or open conditions in various rear light circuits.

John
[link:www.goldengatemark8.com|Golden Gate Mark VIII Website]
http://mark8.org/users/johnaec/Mark_VIII_s.jpg
'97 Mark VIII LSC
'96 T-Bird 4.6L
 
RE: Stop Lights / Turn Signal Inop

Your problem is at the Multifunction Switch (Turn/Wiper/Washer/Highbeam Switch).

You have a dual filament rear light system- one filament is marker, the other is both brake and signal. If you step on the brakes, power comes from fuse 11 in the dash fuse box, through the brake pedal switch to the multifunction switch, which sends power to both taillamps. If you use the turn signals, the multifunction recieves power from fuse 10 of the dash fuse box and sends it to the appropriate side.
The tell-tale clue is your upper brake light- it is powered directly from the brake switch, without passing through the multifunction switch. The fact that it works proves the brake switch and fuse 11 are good.

You didn't say whether your front signals or 4-ways function correctly. That would give me more helpful information, but let's continue as if my theory is correct.

Undo the steering column shrouds by removing the lower trim panel, twisting out the tilt lever with a small pair of vise-grips, and removing the Phillips screws that go up through the holes in the lower shroud half. Undo the two Torx screws holding the switch to the inner column bracket and bring it out so you can probe the connector with a test light.
This may be all you need to do; I have seen a number of times where repeated tilting of the column has caused the connector to come unplugged from the switch!

If it's OK:

Step on the brake pedal. You should have power at the Light Green and the Light Green/Red wires into the switch.
This power should go through the switch and come out at the Light Green/Orange wire (Left Rear Brake and Signal feed) and Orange (Right Rear Brake and Signal feed) If you don't have output on those two wires, replace the switch.

Turn the key on. You should have power on the White/Light Blue wire. This is directly from fuse 10. Push the turn signal lever to each side, and see if you have power on each rear feed. If not, replace the switch.

I'm using my crystal ball now, and predicting you won't have output feed. If you did, and we were dealing with open circuits to the rear lights, your signal indicators on the cluster would still work, because they're the first things to be powered by those feeds.

I hope this helps. If not, I can give you more information if you give me more information.
-Do the front signals work?
-Do the 4-ways work?
-Do the dash indicators flash? If they do, are they flashing very quickly?
 
RE: Stop Lights / Turn Signal Inop

FrankieX-

Thanks for the extensive reply.

I have checked further per your directions and can report the following:

-Do the front signals work? ---NO THEY DO NOT
-Do the 4-ways work? - NOTHING AT ALL
-Do the dash indicators flash? If they do, are they flashing very quickly? -----NO, THEY DO NOTHING

>>>>>I DID DOUBLE CHECK FUSE 10 & 11, BOTH ARE GOOD.


THANKS AGAIN
 
RE: Stop Lights / Turn Signal Inop

OK, now I am even more convinced the problem is in the column; either internal in the switch or poor contact in the connector to the switch.

You'll have to get in there and check.

Something else to try: if you push the hazard button on and off rapidly 7-8 times while closing one eye and thinking positive thoughts, you may jar the internal switch contacts enough to get the signals working again TEMPORARILY. This is not a fix; it just will prove you need a switch.
On the other hand, if it doesn't work, that DOES NOT prove you DON'T need a switch. You'll still have to test it.

Keep me posted.
 
RE: Stop Lights / Turn Signal Inop

Frankie X-

Agin, thanks.......

I disassembled the column utilizing your instructions, no problems. Found both connectors firmly seated with both clips on each connector seated. With a VOM,

I determined the following:


Step on the brake pedal. You should have power at the Light Green and the Light Green/Red wires into the switch.

>>>Found 12 VDC proper wires.

This power should go through the switch and come out at the Light Green/Orange wire (Left Rear Brake and Signal feed) and Orange (Right Rear Brake and Signal feed) If you don't have output on those two wires, replace the switch.

>>>>>Had no voltage coming out of the switch.

Turn the key on. You should have power on the White/Light Blue wire. This is directly from fuse 10. Push the turn signal lever to each side, and see if you have power on each rear feed. If not, replace the switch.

>>>>>> With key ON, 12 VDC on the WH/BL, but no voltage on the output side.

>>>>Looks as if the switch is DOA, will attempt to locate one tomorrow. If the local dealer does not have one, do you have on-line sources?

Mark
 
RE: Stop Lights / Turn Signal Inop

These switches are used for more than one model applications. Getting one shouldn't be a problem.

If you want to get one online, contact Max at 5-Star Ford. there is a listing in LOD's vendor section.
 
RE: Stop Lights / Turn Signal Inop

:)

FramkieX-

PROBLEM SOLVED. Thanks to your advice, I replaced the switch and the problem is fixed. Acquired a part locally.

YEA ! Saved a bundle......Much thanks

Mark:D
 
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