Why don't my turn signals work?

mercury

#1

I have a 1996 Mercury Grand Marquis. My turn signals, brake lights and 4way/hazzard lights will not work. I replaced all the fuses and it didn’t help. I’ve ruled out the multi-function switch because everything else on the car works just fine.

If you know what it might be, PLEASE let me know. Also, what will it cost to fix?

Thank you soooooo much!


#2

No one can tell you what it will cost because this will be a by the hour trouble-shooting process and you won’t know how long it will take to find out the problem.Your turn signal and hazard flashers are in the fuse box inside the car, try replacing one of them before you take it someplace to get it fixed.


#3

Does the green left/right indicators on the dashboard illuminate when the turn signal switch is turned to either direction and does it illuminate when the hazard switch is activated?
(knowing this helps in trying to form an answer)


#4

I don’t see how you can rule out the multi-function switch since all the circuits you mention that are having trouble run through it and as far as I know that is the only things. I would first verify power is getting to the switch. Even though the fuse is ok there may be a problem with the power wire to it.


#5

The multi-function switch also controls the high-beam headlights and the windshield wipers. However, I fully agree that just because those things are working you can not rule out the multi-function switch.


#6

Thanks for the info Tardis and you are correct. I was thinking of a different switch in my previous post. I was thinking of the switch that ties for the emergency flashers. All the tail light circuits run through that switch I believe so I would check it out. (After looking at some data it is the MF switch I was thinking of. Not a seperate switch as I had thought.)


#7

I was able to find some data on the Autozone website. There is a lighting module tied to the multifunction switch and the power for the rear lights passes through it. It looks like there should be power coming from the module on a light blue wire to the MF switch. Make sure there is power there. Power comes from fuse #5 when the emergency flashers are off. It comes from fuse #1 when they are on. Since it appears the lights don’t work in either position the lighting module is the common point of possible trouble.

The middle brake light should be working since it bypasses the MF switch. Check fuse #1 and the bulbs if it doesn’t work.


#8

Like cougar & Tardis I would say that the MFS/multifunction switch is the prime suspect on this.

From the ETM/electrical troubleshooting manual for my 95 Taurus, a good MFS will pass all of the following VERY VERY simple tests.

1.Flash to pass circuit
2.dimmer high & low beams circuit
3.Left/right turn circuit
4.Hazard switch circuit
5.Stop lamp pass thru circuit.
6. Cornering lamps circuit.

An example is the brake light pass thru test.

To test, connect an ohm meter to MFS terminals 810 & 9 Hazard switch off turn signal switch set to neutral. A good switch will read closed circuit.

The MFS on your Mercury needs to be tested


#9

I just had this problem with my Mercury grand Marquis I have a1996 too it is the control module for your lights it was 300 dollars I don’t have that kind of money right now so I ran a jumper wire from the fuse box to the brake light switch the bottom wire close to the floor is the hot wire for the brake light switch run a wire from a hot all the time fuse then run it to the brake light switch and all your brake light turn signals and four way flashers will work also if is stuck in park that will be fixed too


#10

I would hope they solved this problem 9 years ago.