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Dim Sequential Tail Lights

Started by Calypso Coral, June 16, 2023, 02:45:37 PM

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Calypso Coral

My 69 GT500 has dim turn signal first bulb in the series on either side is the brightest, but still dim. The remainder are barely noticeable. Brake and stop lights are fine. Inspected the grounds and even introduced an external ground, but still dim. Replaced bulbs and no change, Any insight?
Thanks

propayne

President, Delmarva Cougar Club - Brand Manager, Cougar Club of America

Cobrask8

#2
A regular topic, and usually the same culprits:

Low battery/Charging system
Dirty or painted grounds
dirty/corroded wire harness connections in WHOLE car
inadequate battery grounding
Old weak battery
Burned contacts on turn signal switch
Seq unit in trunk has issues (Usually just a go/no go)
Toasted flasher (Replace with EL-12 relay flasher)

Get out the wire brush and contact cleaner, get to work, and after check with engine running.

Dan

gt350bp

My 68KR had the same issues and I contacted Vic at Cougars Unlimited, and he fixed me up with two flashers and new LED bulbs. Big difference but still need to have the engine running for all bulbs to flash and be bright.

Don
gt350bp

Calypso Coral

I appreciate all the suggestions. Grounds are fine, first thing I checked, battery fairly new and fully charged. I'll look into the other suggestions.
Thanks

Calypso Coral

Cobrask8, where can I find the article (On the blink) online? I tried downloading the images, but they are not so legible.
Thanks

shelbydoug

It seems that the brightness just dims with time no matter what solution you try.

It does have to do with insufficient grounding of the system but the question is exactly where.

I installed a system made by the Mustang Project. It fixes the problem with one "little" change. You loose the quick flash through the brake light as the original system did.

In questioning that change, ironically they said that they were told by "an expert" that the brakes were not supposed to do that so they took it out of the system "at much effort!"

The sequentials work perfectly though and the lights are nice and bright. No longer do you loose sight of the lights in the bright sun light.

68 GT350 Lives Matter!

5s386


I just purchased a LED rear brake light system and it works great! Not cheap, but satisfied.

mr68shelby

The wiring harness from the dash to the rear of the car was the problem on my brother's car. Mike

Calypso Coral

Appreciate all the help. I can tell you replacing the bulbs to 1157 Led equivalent works for driving lights, but not brake and turn signals without some modification.

Cobrask8

Calypso,

I wrote that almost 20 years ago! PM me with your e-mail, and I'll send to you

During my years as a tech editor for Hemmings.

Dan

shelbymann1970

Shelby owner since 1984
SAAC member since 1990
1970 GT350 4 speed(owned since 1985).
  MCA gold 2003(not anymore)
1969 Mach1 428SCJ 4 speed R-code (owned since 2013)

69 GT350 Vert

Often, the alternator doesn't charge the battery at idle speed.  The alternators in the link below work well and have a smaller pulley that allows charging at idle.  The OEM length belt wasn't too long and adjusted just fine.  Made in ohio and under $100.

https://www.tuffstuffperformance.com/i-24486283-alternator-70-amp-oem-wire-v-grove-pulley-external-regulator-factory-cast-plus-7078.html?ref=category:1267421

shelbymann1970

Quote from: 69 GT350 Vert on June 27, 2023, 07:53:28 AM
Often, the alternator doesn't charge the battery at idle speed.  The alternators in the link below work well and have a smaller pulley that allows charging at idle.  The OEM length belt wasn't too long and adjusted just fine.  Made in ohio and under $100.

https://www.tuffstuffperformance.com/i-24486283-alternator-70-amp-oem-wire-v-grove-pulley-external-regulator-factory-cast-plus-7078.html?ref=category:1267421
NPD sells them according to their dealer locator-at least the one in Mi. I'm thinking of buying a Jack Brooks Dead Nuts on Alternator. I wonder if anyone here has used one? I got zero issues though with my electronic LED setup.
Shelby owner since 1984
SAAC member since 1990
1970 GT350 4 speed(owned since 1985).
  MCA gold 2003(not anymore)
1969 Mach1 428SCJ 4 speed R-code (owned since 2013)

69 GT350 Vert

#14
I have been running a dead nuts on alternator for 11 years without any problems.  However it is only 55amps and didn't charge at idle speed. 

Summit sells the tuff stuff alternators.  They also make excellent starters.