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Discussion Starter #1
so heres the situation. yesterday I went outside to sit in the car and listen to some music while my cousin was out in his 01 ses parked beside me detailing his interior. well I put the ignition in accessory mode and was listening to the radio. next thing i know i notice my HI Beam indicator lamp is on. - no other indicators wew on. just it. so i was like "Hummm WTF?" so I played with my headlight switch and the multi function switch and couldnt get the indicator lamp's state to change (turn off) so I got out and glanced at the headlights. they didnt appear to be on. (I added autolamps and RAP to my car) so anyways I was alittle curious as to what was going on so I turned the ignition to the off position and removed the key - same deal. HI Beam indicator was stuck on. At this point I became concerned about battery drain from the indicator. so I turned the headlight switch tot he on position and the HI Beam indicator went off. but the HI Beams on and had the indicator. Started the car. disabled autolamps and checked DRL operation by looking at the headlights. I couldnt tell if they were flickering but they were definately working. - just with the stuck indicator. looked at the wiring diagrams and searched the forums and found where Nidan had spoken of the DRL Module failing and the high beam indicator being stuck on.... so I removed the DRL Module. - then I had high and low beams but NO high beam indicator. so i ended up jumpering pins 1 and 8 1 being "Hi beam indicator output" and 8 being "Hi beam input" in connector C186 (the DRL module connector) (above circuit referenced from 1997 EVTM)
I then had normal operation of the headlamps minus DRL's.

So. I began looking for ways to open up the DRL module (LSOTD Module) I found it had this crusty enamel cement type material at it's base. I discovered a square black plastic Cap that you can remove with a hammer and flattip screwdriver at the edge of it then pry up. under that i observed a U shaped piece of aluminium that is stuck down between the two transistors that run the DRL circuit. I then hit a deadend trying to figure out how to open it up more to get the whole board out. well i dug around with the flattip and a knife and found 4 bolts that you take out. and you push down with the module on the floor on the connector and then the whole board comes loose from the top (connector + bottom seal + pc board )
note that there are two clear plastic insulating tabs between the transistors and the top heatsink. they must remain in place. So i got my PCB out and looked at it and it is definately burnt. what I'm trying to figure out now is why it burned and how i can repair it. PICS:


DRL Module


DRL Bolts, End cap & aluminium intenral heatsink component




DRL Module Opened.


Heatsink + Insulator tabs

[image=width=400]http://spindrive.mine.nu/tcca/drl/DSCF0597.JPG[/image]
[image=width=400]http://spindrive.mine.nu/tcca/drl/DSCF0598.JPG[/image]
[image=width=400]http://spindrive.mine.nu/tcca/drl/DSCF0601.JPG[/image]
[image=width=400]http://spindrive.mine.nu/tcca/drl/DSCF0602.JPG[/image]
Burnt PCB


Now the question - WHY did it fail? the car is at 96758 Miles when it died :(

[image=width=400]http://spindrive.mine.nu/tcca/drl/DSCF0573.JPG[/image]

The timer IC inside the module is a ST Microelectronics SA555N
http://www.datasheetarchive.com/pdf-datash...pdf-2/26675.pdf
 

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Looks like a lot of white aluminum corrosion in that housing-water penetration shorting it out maybe? I do know that there were a lot of failures of these things on the first two years of the 3rd gen Taurus models.
 

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Discussion Starter #4
ok :) I have the module working again. I'm going to have to evaluate it for fire risk though since it is unknown what caused the failure in the first place. it happened on a circuit that is claimed to be "NOT USED" in the 1997 Ford EVTM (wiring diagrams) which i find odd.

as for the autolamps I had to go to the local Junkyard and get the autolamp switch and the light sensor / amplifier and the half of the power distribution box (BJB) plastic piece that contained the autolamp headlamp and autolamp park relays and their sockets. then I had to create some new wiring between the BJB and the headlamp switch and the headlamp switch and the light sensor / amplifier. It wasnt extremely hard to do but it WAS time consuming planning it out and making those harnesses and making sure they were safe and not a fire hazard / wouldnt pose an intermittent connection issue in the future from vibration / corosion. (shrinkwrapped the connections in order to help with this).

[image=width=400]http://spindrive.mine.nu/tcca/drl/problem.jpg[/image]
proposed repair

[image=width=400]http://spindrive.mine.nu/tcca/drl/repair.jpg[/image]
Completed repair

[image=width=400]http://spindrive.mine.nu/tcca/drl/repair2.jpg[/image]
liquid electrical tape FTW :)
 
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