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Shift Light, 1988 Fiero GT by dbober
Started on: 05-25-2015 12:45 PM
Replies: 15 (463 views)
Last post by: dbober on 05-31-2015 01:02 PM
dbober
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Report this Post05-25-2015 12:45 PM Click Here to See the Profile for dboberClick Here to visit dbober's HomePageSend a Private Message to dboberEdit/Delete MessageReply w/QuoteDirect Link to This Post
Here is a little background, I bought my 1988 Fiero GT in March of 1988. It has the original 2.8 Liter V6 with the Getrag 5-Speed and currently has 27,600 miles on the car. Hasn't been my daily driver in over 25 years, mainly autocross and car shows. According to the 1988 user manual and the factory service manual, there is no up-shift light on the V6, the wiring diagram only shows the up-shift circuit on the 4 cylinder.

While driving to an autocross this past Sunday, the up-shift light started glowing! It wasn't full bright, only the right half started to glow. It didn't follow any kind of pattern, just light up for about a minute and went out. When I arrived at the autocross, it appeared again remained half on when I turned the car off. Huh? Turning the ignition on (engine off) and off again the light when out, and hasn't come on since.

So, this morning, I pulled the cover off the gage cluster and found that there is NO LIGHT OR SOCKET IN THE UP-SHIFT OPENING, IT'S EMPTY! WTH? My first conclusion was perhaps sunlight making it's way into the back of the gage cluster, I was driving into the morning sun when it happened, but not when I parked the car in the pit area. Now, I can reproduce a similar effect with the back cover off of the cluster, but not with the cover back in place. I have not found any evidence of scorching, damage, or delamination of the printed circuit board, that might show evidence of a short circuit, in fact its in excellent condition and no fuses are blown.

Car runs great, no check engine light during or after. Heck, I even placed First in the combined Vintage Class! But I'm at a loss to explain why the up-shift light appeared? As I mentioned earlier, it was not full bright, only the right half started glowing, and I'm sure I wasn't hallucinating.

Any idea's?

Doug
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f85gtron
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Report this Post05-25-2015 01:09 PM Click Here to See the Profile for f85gtronSend a Private Message to f85gtronEdit/Delete MessageReply w/QuoteDirect Link to This Post
Light pollution from an adjacent bulb?
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dbober
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Report this Post05-25-2015 01:36 PM Click Here to See the Profile for dboberClick Here to visit dbober's HomePageSend a Private Message to dboberEdit/Delete MessageReply w/QuoteDirect Link to This Post
Considered light pollution from another bulb, but could not reproduce it. All lights were off when it happened.
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FTF Engineering
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Report this Post05-25-2015 08:24 PM Click Here to See the Profile for FTF EngineeringSend a Private Message to FTF EngineeringEdit/Delete MessageReply w/QuoteDirect Link to This Post
Pics or it didn't happen!!
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Phil
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Report this Post05-26-2015 08:17 AM Click Here to See the Profile for PhilClick Here to Email PhilSend a Private Message to PhilEdit/Delete MessageReply w/QuoteDirect Link to This Post
put an empty socket in the hole
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tshark
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Report this Post05-26-2015 01:16 PM Click Here to See the Profile for tsharkSend a Private Message to tsharkEdit/Delete MessageReply w/QuoteDirect Link to This Post
...

[This message has been edited by tshark (edited 09-08-2018).]

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ninjayogi
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Report this Post05-26-2015 05:53 PM Click Here to See the Profile for ninjayogiClick Here to Email ninjayogiSend a Private Message to ninjayogiEdit/Delete MessageReply w/QuoteDirect Link to This Post
What????? There's a shift light? Which one is it?
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tshark
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Report this Post05-26-2015 06:30 PM Click Here to See the Profile for tsharkSend a Private Message to tsharkEdit/Delete MessageReply w/QuoteDirect Link to This Post
Right side idiot lights, below the turn indicator. Only lights up on the manual tranny-equipped vehicles.
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dbober
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Report this Post05-26-2015 10:08 PM Click Here to See the Profile for dboberClick Here to visit dbober's HomePageSend a Private Message to dboberEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by FTF Engineering:

Pics or it didn't happen!!


LOL! I wish I could have snapped a picture!

Correct, headlights and parking lights were off. As were the turn signals.

Burned out resistors leave an awful odor, not sure what a burned diode smells like, but I don't smell anything. So, I guess it's time to pull the IP cluster...
It's certainly possible that it was sunlight, I was able to shine a flashlight through the vents and some light made it through the up-shift light, but nothing like it appeared on Sunday. Perhaps that's all it was, but I like to have a definitive resolution.

Currently, all lights and gauges work.

I'll report back when I pull the IP Cluster. Thanks folks!

Doug
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Patrick
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Report this Post05-27-2015 12:39 AM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by ninjayogi:

What????? There's a shift light? Which one is it?


Those who've never seen a Shift light get excited at the prospect of having one. Those who've had one learn to remove the bulb.

They're a distracting nuisance!
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FTF Engineering
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Report this Post05-27-2015 09:23 AM Click Here to See the Profile for FTF EngineeringSend a Private Message to FTF EngineeringEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by dbober:
LOL! I wish I could have snapped a picture!


Haha! Yeah, all I got is light somehow getting to the back side of the bulb hole. Somehow. Either sunlight at the perfectly correct angle, or another bulb that was bleeding over. Despite how unlikely, that's all I got.

Good luck with the hunt and I hope you figure it out.
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css9450
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Report this Post05-27-2015 12:31 PM Click Here to See the Profile for css9450Click Here to Email css9450Send a Private Message to css9450Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by FTF Engineering:

Either sunlight at the perfectly correct angle....



I forget which bulb it is (or lack thereof), but I have one that gets sunlight and glows. Requires the perfect sun angle and time of day! Kind of worried me the first time it happened but I doubt I've seen it more than once every couple of years.

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dbober
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Report this Post05-31-2015 08:22 AM Click Here to See the Profile for dboberClick Here to visit dbober's HomePageSend a Private Message to dboberEdit/Delete MessageReply w/QuoteDirect Link to This Post
So, I pulled the IP Cluster and found nothing that would have caused/leaked/whatever light into the Up-Shift light box. No scorched traces on the plastic circuit board on the back of the IP or on the Tachometer. The shift light is on the top right side, and there is nothing near it accept the right turn signal light that might have shorted or burned.
The plasic blocks that seperate the lights were in place and their rubber gaskets are still plyable and positioned correctly, no light leakage. The tachometer board is sound, no burned components.

I considered covering the open socket with tape, but chose not to. I want to see if it happens again and grab a picture.

Removal was easy, so this was a good oppurtunity to clean and polish the gauge lens.
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FTF Engineering
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Report this Post05-31-2015 10:01 AM Click Here to See the Profile for FTF EngineeringSend a Private Message to FTF EngineeringEdit/Delete MessageReply w/QuoteDirect Link to This Post
Well it sounds like you covered all the bases. Don't worry... There are plenty other phenomena in the world that continue to go unexplained.

Aliens
Crop circles
Nessie
Pontiac Aztek
Haggis


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phonedawgz
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Report this Post05-31-2015 10:27 AM Click Here to See the Profile for phonedawgzClick Here to visit phonedawgz's HomePageClick Here to Email phonedawgzSend a Private Message to phonedawgzEdit/Delete MessageReply w/QuoteDirect Link to This Post
When was the last time you saw something electrical glow for a period of time and not smell and not show burnt after? So eliminate that one.

There are no bulbs in the instrument cluster to light up that can't also be seen by the driver, so eliminate that one.

Sunlight is the only thing left. I'll go with that one.
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dbober
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Report this Post05-31-2015 01:02 PM Click Here to See the Profile for dboberClick Here to visit dbober's HomePageSend a Private Message to dboberEdit/Delete MessageReply w/QuoteDirect Link to This Post
Crop circles? Well, funny you mention that...Oh, never mind.

Yes, sun light is the only other explanation. Burnt electronic components leave a foul odor that would have been noticeable for several days.
I just like to have tangible evidence.

Doug
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