My right turn signal operates normally. But, my left has a fast flash much like when a bulb is burnt out. But, what is confusing is all the bulbs are flashing and just as brightly as the right turn signal. Weirder, the left signal flash's faster when I turn on my parking or headlights.

Replaced the front, rear, and instrument cluster bulbs, same fast flash.

Anybody been through this and diagnosed the issue? Any idea what clue the faster flash when lights on might mean?

This has me totally stumped.

 

Yep, I found it was caused by putting in the "Long lasting" Sylvania replacement lamps in the front turn signals. Regular ones seem to work fine.

 

Bulb with a different draw than stock might do it. But I hadn't changed any bulbs before it started, and the bulbs I used to replace in diagnosing were stock out of a parts car. And that doesn't explain why the faster flash when the parking lights are tuned on. Two isolated circuits.

I also swapped out the CPU that holds the flashing unit, problem remains.

The only thing I've did where one of the turn signal bulbs are located before this started was remove and replace the instrument cluster after swapping out my NA speedo for a TII speedo.

 

I had the SAME problem after i removed an aftermarket foglight setup.. never figured it out but i had the EXACT same problem

 

mine does it too, but on the right side. it goes away and comes back on its own...i don't get it.

 

Emac, 1987_Gxl,

The flashing even faster when the lights are turned on is what makes this REALLY confusing. Just curious if it was that exactly the same for either of you two.

If the same for you two, I'm starting to think a faulty turn signal switch as it also recieves 12V to light up with the lighting.

 

it sometimes flashes normal, other times it flashes fast. all my lights work. i haven't checked the switch.

 

Check the wiring behind the bumper, make sure there are no breaks in the wiring, or at the back of the turn signal.

 

Bulb type...

Confirm that the rear bulbs are 1156

and the front bulbs are 1157.

If a 1157 gets forced into the rear turn signal, that will happen.

 

yes it flashed faster when turning lights on, it started happening only after i removed the mounting brackets, and wiring running from the front back through the firewall to the center console.
but it doesn't matter anymore, I sold that car a few years ago and have a really nice 91 fc with all original interior, stock foglights (like the way they look, i have them on all the time with the headlights)
compared to an 87 gxl, with junkyard salvage interoir parts that don't match in color

Is it possible to replace the bulb of the stock fog lamps with something a bit brighter?
also my fog lights will only come on with the headlights up & on, what needs to be to in order to be able to turn the fog lights on/off independantly from the headlights?

 

i havent noticed that it happens when the lights are on vs when they arent. i'll test on the way home from work. the bulbs are the correct bulbs, my problem is still intermittant (and random, pending the light test)

 

it must be your blinker fluid is low, hahaha sorry other than the assinine witicism i got nothing to help ya!

Zak

 

my blinker fluid is DOT 10 lol

 

DOT 10? I've found that 11 works the best along with the Lucas Blinker Fluid Stabilizer.

 

back to the subject at hand.

Icemark,

Would the wrong bulb cause the fast flash to flash faster when the lights are turned on?

 

yes.

Simple to check. The 1156 will have a single contact on the bottom of the bulb, while a 1157 will have two contacts.

1156 in the rear, 1157 in the front

 

Icemark, I'm not familiar with how the "Longer lasting" bulbs work, could you explain it, and why it may have caused the fast blink problem? Please

 

Two different types of long lasting bulbs.

One uses a resistor in the base, the other uses a thicker filiment and a slightly different make up of the gas mixture in the bulb.

Either one could trip the CPU flasher board to think that the resistance is changed. Enough change in the resistance and it sends out the error code of a fast blink.

See the CPU flasher board flashes fast to warn of a bulb out (which it "see's" as change in resistance).

The Stop sensor/Light on the S4 brakes does the same thing. So for example my LED tail lights, I need to add a .5 ohm / 5 watt resistor across the + and - of the brake third brake light to trick the CPU into not seeing the LEDs (LEDs have considerbly less resistance than filiment lights).

 

I have a fully operational 1156 in the left rear, 1157 in the left front.

So, to be safe.I replaced them with new 1156 in the rear, 1157 in the front, still fast flash.

Even though it was working, I replaced the instrument cluster left turn bulb, still fast flash.

I replaced the turn signal switch module, still fast flash.

I swapped out the CPU where the flashing circuit is, still fast flash.

The right turn signal alone flash's properly.

All 6 lights illuminate equally and flash properly with the emergency flasher.

The left turn signal alone, fast flash. I get it that the left turn signal circuit isn't seeing enough resistance, so is giving the warning fast flash.

WHAT THE HECK ELSE IS THERE TO TRY?

I'm considering requesting Holy Water and a Catholic Priest?

 

check out the wires, you might have a short or a bad ground, or something grounding out where it shouldn't. A naked or damaged wire, moisture perhaps? Try replacing fuses. I should think that maybe the switch needs to be fixed, since they behave fine on the emergency switch.

Maybe using the holy water in place of the DOT 11 blinker fluid will do the trick of chasing away your poltergeist, but it's never worked for me.

I really don't see why it's such a pain in the ***... but then again, i never signal.

 

most likley need to replace ur flash relay, my dad had the same problem. works fine now.

 

^ x2

 

by changing out the CPU.

Short in the wiring, yeah. Only thing left. A real pita I'm not looking forward to, especially in todays heat. Over 100 yesterday, and hotter today.

 

It has to be AFTER the CPU considering the right works properly while it's the left that has the fast flash. Only after the CPU is the power to the left independent from the right.

At least less wiring to have to trace.

 

Considering the Battery Tray was changed out recently, suggested I look for a pinched wire. Pulled the tray, no evidence that a wire was even close to being pinched. Shook the wire from all points, no change in the fast flash.

Pulled the entire parking light assembly and replaced with a spare I had, and VA VA Va VOOM. Normal flash. Plugged in the original assembly, fast flash. So, old assembly thrown away, spare assembly installed.

I have no idea why. There is no evidence of corrosion or a weak connection to the bulb otherwise which might make the CPU think the resistance was off. The bulb was flashing just as bright as the other one, so no hint that might be the cause of the fast flash. BUT, there you have it. Problem solved, and the solution is out here for future "search" references.

Now, back to the remainder of my to-do list for my Turbo Vert.

Get the AC working. 103 today.... must have AC. MUST have AC.