Trying to find whats wrong with my old Fem

[HKS]

C726C9E0-6688-4897-9D5D-E046F036ADB6.png

Fredrik,
Just apply +12 volts to the FEM power pins and measure the coil positive voltage. Power (+12v) enters the FEM via C201g pin 3 (the big 4 pin connector). Chassis should be ground.
Careful, if you get the 12 volt polarity wrong. If you reverse the leads then you can, very gently, lay the FEM in the trash can.

I don't see why Ford would use +5 volts and strain the +5 volt regulator even more, and generate even more FEM heat.
It has to be a !2 volt relay.

Or you can use an Ohm meter and check the resistance from pin 3 of C201g to one side of where to coil used to be. It should be close to zero. Relay switching is usually done by switching the ground side, just like all other FEM functions (except for the P Chanel devices like Q35 and Q36).
Hermann

[HKS]

Entering Information overload sector:

Since you have the relay out you might try connecting +3 to 4 volts on the coil and see if it clicks. If not, then it is 12V relay.
Go ahead and ask why not +5 volts.

I assume you already checked the coil continuity.

[HKS]

Fredrik,
I am 99.9% sure that the relay is for the drivers side window up and down.
If the window works (used to work) then the old relay is OK.
HKS

[Fredrik73]

Fredrik,
I am 99.9% sure that the relay is for the drivers side window up and down.
If the window works (used to work) then the old relay is OK.
HKS

Hi Hermann the driver side window did not work with the old FEM
im waiting for the new relays i cant measure on the old one because i broke it.

[caddyfan]

Hi all, I found this forum last week and I am very happy about all the infos and knowledge.
On my wifes 2002 Tbird also the dashlights don´t work.
AC and Radio lights work with dimming.

I removed the FEM and replaced the responsible MOSFET. It was a IRF5305. See pic.
Unfortunalety it still does not work. I bridged pin 1 and 11 at connector C201e and it worked. So fuse and wires are OK.

Any other idea what can be the problem?
I would like to fix it and not to "hardwire" anything.
Greetings, Volker

[HKS]

Hi all, I found this forum last week and I am very happy about all the infos and knowledge.
On my wifes 2002 Tbird also the dashlights don´t work.
AC and Radio lights work with dimming.

I removed the FEM and replaced the responsible MOSFET. It was a IRF5305. See pic.
Unfortunalety it still does not work. I bridged pin 1 and 11 at connector C201e and it worked. So fuse and wires are OK.

Any other idea what can be the problem?
I would like to fix it and not to "hardwire" anything.
Greetings, Volker

Did you replace Q36 which controls PWM power to the instrument cluster? What type is the IRF5305. Is it P or N channel?
Q36 is not where you pencil is pointing. Q36 is located in the top right corner (right side up, viewed as installed in 2002).
HKS

[caddyfan]

Did you replace Q36 which controls PWM power to the instrument cluster? What type is the IRF5305. Is it P or N channel?
Q36 is not where you pencil is pointing. Q36 is located in the top right corner (right side up, viewed as installed in 2002).
HKS

Yes I replaced Q36, see pic.
Q36 is connected directly to output pin 11 - going to all the lights.
IRF5305 is P-Channel. Same was original installed.
Good device, 31 A max currentYes I replaced Q36, see pic.

[caddyfan]

Did you replace Q36 which controls PWM power to the instrument cluster? What type is the IRF5305. Is it P or N channel?
Q36 is not where you pencil is pointing. Q36 is located in the top right corner (right side up, viewed as installed in 2002).
HKS

Q36 is triggered by the data bus SCP system.
Do deep in the system.
Looks like I must quit here and work with a relays controlled by the driving lamp output, without dimming option

[HKS]

Q36 is triggered by the data bus SCP system.
Do deep in the system.
Looks like I must quit here and work with a relays controlled by the driving lamp output, without dimming option

You are right. I should have noticed the blank spots on the right meant for other/deleted MOSFETS.
Did you test the old Q36 to see if it worked like a P channel MOSFET?
HKS
P.S. I drive with the instrument lights full on, always. Just like hardwired.

One more question.
Does the Dimming wheel on the instrument panel dim anything at all?
If it dims the Radio then the fault can be in the instrument panel which is removable and can be sent in for repair.
Options:
https://www.thunderbirdnest.com/foru...02-thunderbird

[caddyfan]

You are right. I should have noticed the blank spots on the right meant for other/deleted MOSFETS.
Did you test the old Q36 to see if it worked like a P channel MOSFET?
HKS
P.S. I drive with the instrument lights full on, always. Just like hardwired.

One more question.
Does the Dimming wheel on the instrument panel dim anything at all?
If it dims the Radio then the fault can be in the instrument panel which is removable and can be sent in for repair.
Options:
https://www.thunderbirdnest.com/foru...02-thunderbird

I have not tested the Q36. Dimming AC and Radio panel still works, also the odometer
Anyway it is solved now. I installed a relais inside the FEM. See pic. Easy to solder to socket internal pins. No wire cutting needed

[HKS]

I have not tested the Q36. Dimming AC and Radio panel still works, also the odometer
Anyway it is solved now. I installed a relais inside the FEM. See pic. Easy to solder to socket internal pins. No wire cutting needed

Is this the pin C201a #6 labeled exterior lamps? On my schematic, this pin is not numbered. If so, you are getting instrument lighting power whenever lights are turned on. Is this right?
HKS

[caddyfan]

Is this the pin C201a #6 labeled exterior lamps? On my schematic, this pin is not numbered. If so, you are getting instrument lighting power whenever lights are turned on. Is this right?
HKS

Yes correct, C201a #6 is "driving lamp left".
Page 92-2
Most easy to access inside pin. I get instrument lighting power when lights are switched on, either parking or regular headlights

[HKS]

Yes correct, C201a #6 is "driving lamp left".
Page 92-2
Most easy to access inside pin. I get instrument lighting power when lights are switched on, either parking or regular headlights

Excellent solution Volker.

Like I said, the 2002 lights are so dim that I always drive with lights full bright.
Maybe the 2003-5 Tbirds were made brighter after Ford realized the original lighting screw-up.
Hermann

[Fredrik73]

I have not tested the Q36. Dimming AC and Radio panel still works, also the odometer
Anyway it is solved now. I installed a relais inside the FEM. See pic. Easy to solder to socket internal pins. No wire cutting needed

Hi Volker
this was a nice solution i must remember this if i get more problem in the future.
im still waiting for my relays from china
/Fredrik

[Fredrik73]

I have not tested the Q36. Dimming AC and Radio panel still works, also the odometer
Anyway it is solved now. I installed a relais inside the FEM. See pic. Easy to solder to socket internal pins. No wire cutting needed

Hi Volker
on what page did you make that diagram i cant find it
/Fredrik