KeithH said:
My dash indicator has always been on since I had the car. MY tail lights all work just fine though. People always ask what the light is, I say it means the car is in Fast mode. They buy it too because the lines behind the car....
Tail Lamp Failure Module Information
- Thread starter CRE
- Start date
My dash indicator has always been on since I had the car. MY tail lights all work just fine though. People always ask what the light is, I say it means the car is in Fast mode. They buy it too because the lines behind the car....
suprabad said:
I don't know that it's worth any time... I just figured I'd post up a little info for all the cheap people.
iwannadie said:
Wow, fast cars and slow people... I sure hope you're joking. :3d_frown:
CRE said:I don't know that it's worth any time... I just figured I'd post up a little info for all the cheap people.
It's not just cheap people. There is also the issue of getting the tailights to work with LED bulbs, not to mention that some of us just like our cars to be "right". Some people don't give a damn as long as it starts and gets them where they're going. God bless 'em, but I fall into the "want their cars to be right" group.
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suprabad said:
Precisely why I posted this thread. Thank you, I just like hearing someone say that once in a while.
Here's the common failure point. If you'd rather not replace yours any time soon I'd recommend beefing up the jumper. 14ga copper wire would work very well and provide enough overhead to account for premature aging due to excessive moisture.
Although just doubling up the jumper and adding a piece of shielded 18ga wire to the back of the circuit should do nicely.
To continue the explanation of this circuit - A comparator operates like a MAP sensor in that it doesn't sit in the middle of the circuit it's monitoring. It just samples from the side. As such, unless there is a strong power surge or water damage, the comparator and the simple components which interact with it this part of the circuit are rarely found to be the cause of failure (on either the brake or marker side).
I am not certain of the purpose or need for the unidentified component or the break in the power flow leading to the marker lamps. Whether it's a matter of filtering out noise or perhaps buffering the power, there are better ways to handle it.
A FAR better way of handling this entire circuit would have been the elimination of brakes in the marker and brake lighting power routing. Then, using crimp connections (NO solder joints) "T" off from the harness to supply the circuit with power and sample the reference signals. Running with the system converted in this fashion will prevent power disruption to the lights even if the lamp failure module should fail.
By the way, this is a prime example of a situation where crimped connections are FAR more reliable than soldered junctions. Soldered junctions, while less susceptible to an increase in resistance due to oxidization, are far more likely to break due to damage incurred from the constant cooling and heating of the junction.
I am not certain of the purpose or need for the unidentified component or the break in the power flow leading to the marker lamps. Whether it's a matter of filtering out noise or perhaps buffering the power, there are better ways to handle it.
A FAR better way of handling this entire circuit would have been the elimination of brakes in the marker and brake lighting power routing. Then, using crimp connections (NO solder joints) "T" off from the harness to supply the circuit with power and sample the reference signals. Running with the system converted in this fashion will prevent power disruption to the lights even if the lamp failure module should fail.
By the way, this is a prime example of a situation where crimped connections are FAR more reliable than soldered junctions. Soldered junctions, while less susceptible to an increase in resistance due to oxidization, are far more likely to break due to damage incurred from the constant cooling and heating of the junction.
I am aware that this thread is rather old but I still want to make a reply since I have some info relevant to the original post & I found this while searching for a solution.
My car is an '88 with the factory spoiler & 1156 (non-LED) center stop lamp, and had the yellow box. I had replaced all the tail/stop/turn/backup bulbs with new Sylvanias. My dash lamp would come on a couple of seconds after stepping on the brake pedal. I made a check of the lights externally & saw all 5 brakes were on & all 4 tails were OK.
I checked the wiring to the failure box per the FSM & the only weird voltage I got was 2.xV on pin 3 (should have been 12V). I can't explain this since this is the wire that comes from the dash light and it looks like it should have 12V.
I dissected my box & saw the connections looked OK, nothing burned. My resistor values were different than those posted so far:
R1: Red-Black-Orange-Gold for 20K ohms
R2: Yellow-Orange-Orange-Gold for 43K ohms
I have been working on this car off & on for almost 2 years. Prior to getting it, it had sat outside a long time and gone to pot. In the process of making repairs, I used a '91 for a parts car. I couldn't remember if I had swapped out the tail light holders or not, which added to the possibilities for varied resistance (although it was still 27W x 5 and 8W x 4 regardless).
Looking at the info from the thread, I figured I had an offbeat box, since the other 88 boxes used different resistors. I picked up a resistor pack from Radio Shack and tried a few combinations (22/51, 22/35, 27/51), all with the same (original) result.
When I looked at the lamps more closely, I noted for the stop lamps, in each lamp one bulb looked brighter than the other. This was confirmed when I popped the lamp holders out. It was hard to see the difference in the daylight with the holders in place.
My problem was a bad ground wire at one of the sockets in each assembly. I cleaned each & reinstalled it and both bulbs were bright. The dash lamp was also now off for good. It was actually working as designed, since two of the bulbs had problems.
As a side note, I did some testing with the various resistors in place (box out of car) and the values were the same with the several R1 and R2 resistors, 3.4 for R1 and 3.7 for R2, so they are not too sensitive if you need to fix the box and can't find the exact value you had.
Hopefully this will help another in the same situation in the future.
My car is an '88 with the factory spoiler & 1156 (non-LED) center stop lamp, and had the yellow box. I had replaced all the tail/stop/turn/backup bulbs with new Sylvanias. My dash lamp would come on a couple of seconds after stepping on the brake pedal. I made a check of the lights externally & saw all 5 brakes were on & all 4 tails were OK.
I checked the wiring to the failure box per the FSM & the only weird voltage I got was 2.xV on pin 3 (should have been 12V). I can't explain this since this is the wire that comes from the dash light and it looks like it should have 12V.
I dissected my box & saw the connections looked OK, nothing burned. My resistor values were different than those posted so far:
R1: Red-Black-Orange-Gold for 20K ohms
R2: Yellow-Orange-Orange-Gold for 43K ohms
I have been working on this car off & on for almost 2 years. Prior to getting it, it had sat outside a long time and gone to pot. In the process of making repairs, I used a '91 for a parts car. I couldn't remember if I had swapped out the tail light holders or not, which added to the possibilities for varied resistance (although it was still 27W x 5 and 8W x 4 regardless).
Looking at the info from the thread, I figured I had an offbeat box, since the other 88 boxes used different resistors. I picked up a resistor pack from Radio Shack and tried a few combinations (22/51, 22/35, 27/51), all with the same (original) result.
When I looked at the lamps more closely, I noted for the stop lamps, in each lamp one bulb looked brighter than the other. This was confirmed when I popped the lamp holders out. It was hard to see the difference in the daylight with the holders in place.
My problem was a bad ground wire at one of the sockets in each assembly. I cleaned each & reinstalled it and both bulbs were bright. The dash lamp was also now off for good. It was actually working as designed, since two of the bulbs had problems.
As a side note, I did some testing with the various resistors in place (box out of car) and the values were the same with the several R1 and R2 resistors, 3.4 for R1 and 3.7 for R2, so they are not too sensitive if you need to fix the box and can't find the exact value you had.
Hopefully this will help another in the same situation in the future.
CRE;644832 said:
I was just about to the end of my patience with this problem; a week ago I removed the entire taillight assembly from the car. I scoured out all the pigtails, worked over the grounds, replaced all the bulbs, resealed the lens housings and at the end….no joy. That stupid little amber warning light was mocking me all week. I decided that I could live without it.
It took about an hour and I found it very helpful to remove the 3 10mm nuts from the wiring harness brackets to give enough slack for stripping and crimping.
Other common places for ground issues are inside the sockets themselves and the chasis ground points. Some people have found that simply cleaning the ground points worked, I remember one person had to run a new ground line from the front of the car to the rear.
If it's a voltage drop issue but your tail lamps all function properly you can recalibrate the LFM to operate correctly despite the aged wiring.
As for bypassing the LFM, I'd just pull the connector out of the LFM and solder together a small plug in bypass box.
If it's a voltage drop issue but your tail lamps all function properly you can recalibrate the LFM to operate correctly despite the aged wiring.
As for bypassing the LFM, I'd just pull the connector out of the LFM and solder together a small plug in bypass box.
CRE - i dont suppose you have a schematic for the stock circuit, do you? Seems like it would be pretty easy to make a dozen or so PCB's that way, and you could have a 'roll your own' failure module, and would ensure that members can get parts when the existing stock of second hand and new ones run out.
The problem with that is iirc one of the parts is an ASIC because of the timer function built into it and may be difficult to source. Been so long I could be wrong though.
Never had a problem back there. Been lucky I guess. No leakage, corrosion, nothing. Even all the bulbs are original. I really ought to change them. As for cleaning every lamp and socket voltage drop testing to find the culprit is much easier, followed by a shot of ACF-50. Good stuff.
Never had a problem back there. Been lucky I guess. No leakage, corrosion, nothing. Even all the bulbs are original. I really ought to change them. As for cleaning every lamp and socket voltage drop testing to find the culprit is much easier, followed by a shot of ACF-50. Good stuff.
You got a part number for it? If so, i can probably track it down....after all, i found the blue 7-segments for CRE
Sorry mate, don't have a number. In fact I think the device doesn't sport numbers but I could be wrong. Been a long time since I've been inside one of those things.
Hmm, looks like on page 3 theres a picture of the boards, i can make out the toshiba logo but not the part number
I don't have a TFM handy, but in the integration relay there is a similar type of ASIC for the dome lamp delayed off and so on.
It should be a good test of your searching capabilities:
Toshiba 17G005AP-0012
It should be a good test of your searching capabilities:
Toshiba 17G005AP-0012
Well, i found the datasheet for it
Full part number: TC17G005AP-0012
Package: DIP
It's a CMOS Gate Array (540 gates), apparrently compatible with the 74HC series.
http://www.datasheets.org.uk/pdf/3324509.pdf
Will try looking for the actual components now
Full part number: TC17G005AP-0012
Package: DIP
It's a CMOS Gate Array (540 gates), apparrently compatible with the 74HC series.
http://www.datasheets.org.uk/pdf/3324509.pdf
Will try looking for the actual components now
Oooh - brainwave....as the ASICs aren't the likely failure point, why not remove them from the blown board and resolder to a newer PCB?
If they're not at fault why would you swap them? As for buying new ones I think you're missing an obvious point: true gate arrays are not a form of field programmable logic. That's what makes them ASIC