2005 Headlights on even when no key in ignition | Ford Thunderbird club group 1955-2005 T-Bird models

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2005 Headlights on even when no key in ignition

  • Thread starter Thread starter Golden-2005
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Golden-2005

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2005
05Dave said:
uh



My wife's 2005 came without the fog lights which I was told were not available in Canada. I ordered factory lights and harness but the dealer would not install them as they did not have a drawing. Next time we were in the US, I had a service shop install and connect them. They had a factory drawing. Lights work great.
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I have 2005 bronze a e headlights are staying on whether or not key in ignition . Module masters said replace ,multifunction switch. I did yet same issue. I even removed the switch from the car and still headlights are stuck in on position . Is this a Known issue with the FEM ?

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Golden-2005 said:
I have 2005 bronze a e headlights are staying on whether or not key in ignition . Module masters said replace ,multifunction switch. I did yet same issue. I even removed the switch from the car and still headlights are stuck in on position . Is this a Known issue with the FEM ?
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You stated that the headlights are illuminated whether or not the key is in the ignition. Do you mean that the headlights are on all the time? If so, do you have to disconnect the battery to prevent the headlights from discharging the battery?

Whether or not the key is in the ignition, if you turn the headlight switch to the park or on position the parking lamps and headlamps will illuminate. This is a normal function.

The headlamps are controlled by the FEM and instrument cluster. The headlamp and multifunction switches are hard-wired to the instrument cluster. When the headlamp switch is in any position, the instrument cluster sends a command to the FEM. The FEM processes this information and outputs the appropriate command to the headlamps (which are hard-wired to the FEM). This is the same for the low beams, high beams and flash-to-pass position. In the event of all multifunction switch, all headlamp switch or ignition switch invalid or missing data failures, the low beams will be illuminated.

Let me know if your problem is that the headlights are on all the time or you have to disconnect the battery to prevent the headlights from discharging the battery and I will post the testing procedure.

doug7740
1955 Thunderbird Blue
 
doug7740 said:
You stated that the headlights are illuminated whether or not the key is in the ignition. Do you mean that the headlights are on all the time? If so, do you have to disconnect the battery to prevent the headlights from discharging the battery?

Whether or not the key is in the ignition, if you turn the headlight switch to the park or on position the parking lamps and headlamps will illuminate. This is a normal function.

The headlamps are controlled by the FEM and instrument cluster. The headlamp and multifunction switches are hard-wired to the instrument cluster. When the headlamp switch is in any position, the instrument cluster sends a command to the FEM. The FEM processes this information and outputs the appropriate command to the headlamps (which are hard-wired to the FEM). This is the same for the low beams, high beams and flash-to-pass position. In the event of all multifunction switch, all headlamp switch or ignition switch invalid or missing data failures, the low beams will be illuminated.

Let me know if your problem is that the headlights are on all the time or you have to disconnect the battery to prevent the headlights from discharging the battery and I will post the testing procedure.

doug7740
1955 Thunderbird Blue
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Doug7740
Yes problem is headlights low beams are on all the time . I either disconnect the battery or pull out the left and right headlamp micro fuses in the passenger foot well interior fuse panel - Usually then only drive during daylight hours ;-(

I did not know problem could be any of the bolded items you listed above.

Yes looking forward to testing procedure , thank you in advance ?.

Ken
 
Ken,

As I stated before, the headlights are controlled by the FEM and the instrument cluster. The microprosser in the instrument cluster receives hard wired inputs from the multi-function switch, the main light switch and the sunload sensor. From these inputs the instrument cluster sends a command to the FEM, and the FEM grounds the proper circuit to either turn on the low or high beams. Using a scan tool, the first thing you should do is to check for fault codes stored in the instrument cluster and the FEM.

Headlamp Circuit.jpg

If there are no stored fault codes, then you can use the symptom chart and pinpoint tests to diagnose your headlamp concern.

doug7740
1955 Thunderbird Blue

Symptom Chart.jpg

Pinpoint Test 1.jpg
Pinpoint Test 2.jpg
 
doug7740 said:
Ken,

As I stated before, the headlights are controlled by the FEM and the instrument cluster. The microprosser in the instrument cluster receives hard wired inputs from the multi-function switch, the main light switch and the sunload sensor. From these inputs the instrument cluster sends a command to the FEM, and the FEM grounds the proper circuit to either turn on the low or high beams. Using a scan tool, the first thing you should do is to check for fault codes stored in the instrument cluster and the FEM.

View attachment 28274

If there are no stored fault codes, then you can use the symptom chart and pinpoint tests to diagnose your headlamp concern.

doug7740
1955 Thunderbird Blue

View attachment 28275

View attachment 28276
View attachment 28277
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Doug thank you for sending. I'm heading over to AutoZone to use their code scan tool.
Temporarily I am installing today two separate, wireless disconnect switches.

1st in the trunk on the negative pole the battery. Purpose at the completion of driving to disconnect the battery wirelessly without having to open the trunk.

2nd wireless switch I plan to install between the fem headlight positive or hot wire if I can locate it on a circuit chart exterior to the fem. In this manner I can disconnect wirelessly the headlights,.

I'm installing these two wireless switches because I have not been able so far to figure out the problem about the headlines being on.

I do understand now that there is a malfunction in the fem, or could be simple as hey sensor fail, or maybe just the FEM needs a couple of circuits replaced?

My current location is Lantana 33462 FL.
I'm thinking perhaps there is another Thunderbird owner nearby well maybe knowledgeable and how I go about testing.


I will report the test code numbers that show up from the scan tool.


Thank you for your help Doug ;-]
 
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