Cadillac STS The newest installation of the performance sedan from Cadillac, having replaced the Seville

97 STS left turn signal/brake light problem

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  #1  
Old 04-29-2007, 08:50 PM
Greg in NWA AR's Avatar
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Join Date: Apr 2007
Posts: 2
Default 97 STS left turn signal/brake light problem

I have seen many have similar problem as this but no one has given any suggestions so far as I can tell. I have a wonderful 97 STS with 133,000 miles no accidents, mechanicalor wiring repairs or changes made. The right turn signal works OK front and rear. The right brake lights work OK. On occassion the right turn signal flashes faster than normal- not quite twice normal speed. The left front turn signal OK. Left rear turn signal/brake light appears on wrong bulb filament...uses the same filament as the parking lights. If the headlights are on the left turn signal will not operate, period. I have changed the following parts: headlight switch, turnsignal/hazard switch in steering column, bulbs. NO change. I have run all wiring from rear to dash looking for shorts or any other contact- none found.
I tore into the dash and removed the gauge package to see the wiring harness better and locate the parking light relay; found that Cadillac has a styrene plastic sub frame in the dash from side to side that would require complete disassembly of the interior front to see anything. That's when I said forget this, reassembled evrything and came inside to ask if anyone has any suggestions.
I am ready to rewire the left side rear lights but don't know how to tie into the wiring without upsetting the BCS. Any suggestions greatly appreciated.
About scratched my headbald trying to figure out this one.
Thanks y'all,
Greg
 
  #2  
Old 04-30-2007, 05:58 AM
Join Date: Mar 2007
Posts: 114
Default RE: 97 STS left turn signal/brake light problem

You did not list it, but I am sure, replaced the flasher too, right?

Fast blinking turn signals are almost always due to an open circuit, of which the most obvious is a blown bulb. Other causes can be corroded sockets and a faulty wiring harness. A thorough cleaning of the bulbs' sockets and all the associated connectors would be the first step to go. Once you've established that you have a good connection, smear a dab of silicone (tune-up) grease around to seal off moisture.
 
  #3  
Old 05-20-2007, 11:37 AM
Greg in NWA AR's Avatar
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Default RE: 97 STS left turn signal/brake light problem

Eureka!!! Problem discovered and resolved!!
I have seen many hits about this problem and figure many are experiencing the same.....GREAT NEWS!!! EASY FIX!!!!! The problem is bad bulb sockets! I have discovered that if I removed the blue cover that holds the wires in the socket then pull out on the GROUND (black wire) then the bulb will flash on the correct filament.
Now your asking OK how to make this fix permanent? 2 options as I see it.
1) Cut off the plastic protrusion on the blue cover that pushes the ground wire into the socket then put the cover back in place on the bulb socket and while pulling out the ground wire wrap tape around the ground to keep that outward tension on it.....I did this but doesn't last long.
2) Replace the bulb socket(s) as needed with OEM parts....I really like this best....Don't you?
Well that resloved my problem of the signal and brake light not operating on the correct filament. I must say that it was a long chase to final conclusion. I had rewired from the dash to the tail light unit, tested wiring till blue in the face, tried changing right unit with left unit and that's when I discovered it was in the light unit wiring....or so I thought....untill I finally found out the real cause was bad sockets....I was ready to torch the beasty and sell it to the insurance company just to regain some semblence of sanity....quirky little demon...
Hope this helps some of you out there ready to throw in the towel....like I was!
Enjoy!!!
Greg
 
  #4  
Old 05-20-2007, 01:07 PM
G.A.R.Y.'s Avatar
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Posts: 1,646
Default RE: 97 STS left turn signal/brake light problem

Greg

That was a great post and I'm sure it will come in handy in the future for many of us. Thanks for the results.
 
  #5  
Old 05-20-2007, 02:52 PM
Stealth's Avatar
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Join Date: Feb 2007
Posts: 3,945
Default RE: 97 STS left turn signal/brake light problem

like belagatyo stated, open circuit.
the challenge was FINDING IT!


[sm=happy046.gif][sm=goodidea.gif]


good job, thanks for providing resolution of issue status.
this will help many others to look there first.

i'm tagging this thread as FAQ.




ORIGINAL: Greg in NWA AR

Eureka!!! Problem discovered and resolved!!
I have seen many hits about this problem and figure many are experiencing the same.....GREAT NEWS!!! EASY FIX!!!!! The problem is bad bulb sockets! I have discovered that if I removed the blue cover that holds the wires in the socket then pull out on the GROUND (black wire) then the bulb will flash on the correct filament.
Now your asking OK how to make this fix permanent? 2 options as I see it.
1) Cut off the plastic protrusion on the blue cover that pushes the ground wire into the socket then put the cover back in place on the bulb socket and while pulling out the ground wire wrap tape around the ground to keep that outward tension on it.....I did this but doesn't last long.
2) Replace the bulb socket(s) as needed with OEM parts....I really like this best....Don't you?
Well that resloved my problem of the signal and brake light not operating on the correct filament. I must say that it was a long chase to final conclusion. I had rewired from the dash to the tail light unit, tested wiring till blue in the face, tried changing right unit with left unit and that's when I discovered it was in the light unit wiring....or so I thought....untill I finally found out the real cause was bad sockets....I was ready to torch the beasty and sell it to the insurance company just to regain some semblence of sanity....quirky little demon...
Hope this helps some of you out there ready to throw in the towel....like I was!
Enjoy!!!
Greg
ORIGINAL: belagatyo

You did not list it, but I am sure, replaced the flasher too, right?

Fast blinking turn signals are almost always due to an open circuit, of which the most obvious is a blown bulb. Other causes can be corroded sockets and a faulty wiring harness. A thorough cleaning of the bulbs' sockets and all the associated connectors would be the first step to go. Once you've established that you have a good connection, smear a dab of silicone (tune-up) grease around to seal off moisture.
 
  #6  
Old 03-18-2008, 09:21 PM
Join Date: Mar 2008
Posts: 4
Default RE: 97 STS left turn signal/brake light problem

Yup. Now that I know more about my problem, this is exactly my 94 SLS right tail light problem.

If I had more of an idea on what to search for I would have found this post earlier. Thanks for the confirmation of my problem. Now for the fix.

They were right, this did help in the future.

. . . fb
 
  #7  
Old 08-22-2014, 03:43 PM
chaz97seville's Avatar
Junior Member
Join Date: Aug 2014
Posts: 1
Default Same model, same problem, Different cause

My '97 Seville SLS left brake lights don't work either. But I've eliminated bad sockets, ground faults and the usual suspects.

How hard can it be to fix? Well, all the US models have supply leads that come via the turn signal circuit. I have no power at the yellow left brake supply lead, were as I do show 12 volts at the green right brake supply lead. Tracing the circuit to connector 202, I have voltage at the light blue brake supply lead (cavity A5), and have corresponding voltage at the right green(A6). But no voltage seen at either end of the left yellow(A7) brake supply lead, so it not the connector.

It has to be an issue with the turn signal blinker/hazard switch inside the steering column. NOT an easy fix in my book !
I can't imagine what the issue is other than a broken wire. I thought about jumping voltage directly from the blue supply to the yellow, but without understanding/knowing the actual blinker internal circuit I thought against it.
This was my father's car; it only has 38K miles which seems young for such a problem. But it certainly appears that my father had struggled with it for awhile (things amiss in truck, missing mounting hardware on most of the lenses, etc).
Guess I won't know until I get the column apart. Not looking forward to it, either.
Anyone else seen this problem/cause?
 
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