[4th Gen : 01-07]: Turn signal fast blink diagnosed
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Turn signal fast blink diagnosed
Greetings,
My '03 Grand Caravan was exhibiting fast blink on the right turn signal only.
The symptom was like a a bulb was out, but the bulbs were in working order.
Ultimately, it turned out to be a bad ground on the right front blinker.
Three wires lead to that dual-filament socket:
- parking lamp
- turn lamp
- ground
The two filaments in the 3157A bulb have independent grounds (unlike an 1157 style bulb), but the socket joins these independent grounds together. Here's what was happening:
Current from the turn signal wire was flowing through the turn filament to that filament's ground lead. Then, because ground wasn't well grounded, the current was flowing into the other filament's ground lead (backwards), through the parking filament and away to ground somewhere else, probably through another parking bulb.
The turn signal blinked w/out headlights, but didn't blink with headlights on, because the parking filament doesn't look like a ground when it's illuminated.
I was also able to detect a problem by probing the plug's ground lead from the back side (through the rubber) along the edge of the wire. The ground lead lit my test lamp. That's not supposed to happen.
I'm not sure where the ground failed. Rather than chasing it down I just stripped a bit of the ground wire near the lamp housing and ran a new bit of wire between this point and the battery.
This solved my problem.
I hope my experience helps somebody else!
My '03 Grand Caravan was exhibiting fast blink on the right turn signal only.
The symptom was like a a bulb was out, but the bulbs were in working order.
Ultimately, it turned out to be a bad ground on the right front blinker.
Three wires lead to that dual-filament socket:
- parking lamp
- turn lamp
- ground
The two filaments in the 3157A bulb have independent grounds (unlike an 1157 style bulb), but the socket joins these independent grounds together. Here's what was happening:
Current from the turn signal wire was flowing through the turn filament to that filament's ground lead. Then, because ground wasn't well grounded, the current was flowing into the other filament's ground lead (backwards), through the parking filament and away to ground somewhere else, probably through another parking bulb.
The turn signal blinked w/out headlights, but didn't blink with headlights on, because the parking filament doesn't look like a ground when it's illuminated.
I was also able to detect a problem by probing the plug's ground lead from the back side (through the rubber) along the edge of the wire. The ground lead lit my test lamp. That's not supposed to happen.
I'm not sure where the ground failed. Rather than chasing it down I just stripped a bit of the ground wire near the lamp housing and ran a new bit of wire between this point and the battery.
This solved my problem.
I hope my experience helps somebody else!
Record Breaker
Joined: Feb 2011
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From: SoCal
Nice work. There's not many willing to chase wires. Just one tip. " ran a new bit of wire between this point and the battery." If that means you connected your ground to the negative battery connection, you didn't need to. You can connect it to any bare metal.
BTW - Both left and right front turn signals use a single common ground stud near the front left headlight labeled G102. That ground was good because your left front turn signal worked. That means your problem was either at a splice (S104) that split the ground to the left and right turn signal assembly or the ground wire leading to that splice from the right front turn signal. That splice is very close to the ground stud and it appears it's in an area below the driver's headlight housing.
BTW - Both left and right front turn signals use a single common ground stud near the front left headlight labeled G102. That ground was good because your left front turn signal worked. That means your problem was either at a splice (S104) that split the ground to the left and right turn signal assembly or the ground wire leading to that splice from the right front turn signal. That splice is very close to the ground stud and it appears it's in an area below the driver's headlight housing.
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Hey, thanks for all the additional detail!
Yes, I connected to the negative side of the battery.
Agree, it's kinda far away and absolutely hideous, but no other clean-ish metal spots jumped out at me in the moment.
Thanks again!
Yes, I connected to the negative side of the battery.
Agree, it's kinda far away and absolutely hideous, but no other clean-ish metal spots jumped out at me in the moment.
Thanks again!
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Possible Solution Bad Ground
Thank you to others for sharing thier information here as it helped lead me to find my issue. I know I'm posting this years later but I just wanted to pass it on if it helps others like it did me.
I have a 2007 Dodge Grand Caravan and the Front Passanger parking light/turn signal was out (1 bulb does both turn signal and parking light).
When I would put the right turn signal on, it would flash fast in the vehicle and only rear passanger light only. Before I got the Van from my father, this same issue happened to the drivers side which was fixed by a mechanic's shop I found out later while trying to figure this out.
I found that it was not the bulb, and not the socket holding the bulb that plugs into the vehicle harness connector, It was a bad ground somewhere down the wire going away from the connector into vehicle.
So here is what I found. On the plug it has 3 wires going into the socket, 2 outside wires should both measure ground and middle wire 12 volts.
so its : Ground / 12 Volts / Ground
I had : Ground / 12 Volts / No Reading , Which told me it was a bad ground.
To fix the bad ground, I choose 1 metal side of the wall in the metal "box" behind the head light for the ground connection making sure the headlight clears connection point going back in. Why the wall not the bottom? Bottom had residue telling me water collects there where the wall did not letting condensation and water run down staying dryer. That and the side mechanics shop fixed choose bottom and thier nuts and bolts used was rusted pretty bad. Cant fight mother nature she will get your connection if she wants and everything will rust and corrode eventually, but you can at least make better choices. Use dielectric greece and solder wires together if you want to maximize results to last longest. I personally did not, neither did the mechanic shop.
7 years of MECP experience and 1,000's of vehicles is where I'm coming from. Love that Mechanic shop also, Family Mechanic.
Make sure you sand the paint down to bare metal and secure it with a self tapping screw, star washer, ring terminal with using 12 or 16 awg stranded copper (OFC Oxogen Free Copper prefered) tapping into bad factory ground running to your new ground point.
Hope this helps someone else like it did me.
Thank you again all who commented here for helping me and others alike!
I have a 2007 Dodge Grand Caravan and the Front Passanger parking light/turn signal was out (1 bulb does both turn signal and parking light).
When I would put the right turn signal on, it would flash fast in the vehicle and only rear passanger light only. Before I got the Van from my father, this same issue happened to the drivers side which was fixed by a mechanic's shop I found out later while trying to figure this out.
I found that it was not the bulb, and not the socket holding the bulb that plugs into the vehicle harness connector, It was a bad ground somewhere down the wire going away from the connector into vehicle.
So here is what I found. On the plug it has 3 wires going into the socket, 2 outside wires should both measure ground and middle wire 12 volts.
so its : Ground / 12 Volts / Ground
I had : Ground / 12 Volts / No Reading , Which told me it was a bad ground.
To fix the bad ground, I choose 1 metal side of the wall in the metal "box" behind the head light for the ground connection making sure the headlight clears connection point going back in. Why the wall not the bottom? Bottom had residue telling me water collects there where the wall did not letting condensation and water run down staying dryer. That and the side mechanics shop fixed choose bottom and thier nuts and bolts used was rusted pretty bad. Cant fight mother nature she will get your connection if she wants and everything will rust and corrode eventually, but you can at least make better choices. Use dielectric greece and solder wires together if you want to maximize results to last longest. I personally did not, neither did the mechanic shop.
7 years of MECP experience and 1,000's of vehicles is where I'm coming from. Love that Mechanic shop also, Family Mechanic.
Make sure you sand the paint down to bare metal and secure it with a self tapping screw, star washer, ring terminal with using 12 or 16 awg stranded copper (OFC Oxogen Free Copper prefered) tapping into bad factory ground running to your new ground point.
Hope this helps someone else like it did me.
Thank you again all who commented here for helping me and others alike!
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I've wound up reading enough threads that ended with "never mind, figured it out" that I also appreciate people who take the time to share their wisdom like this, so <high five> to a like-minded soul for wanting to share.
In the time since I created this thread, I found the bad ground culprit. The clue was in a YouTube video from a mechanic shop. As I remember, he briefly showed a computer screen from an electronic repair manual that showed the location of the ground. It's a ring terminal where several grounds collect near the bottom corner of the radiator on the driver's side (US vehicle). All of these wires are crimped together into the same terminal which is bolted to a vertical surface facing toward the rear of the vehicle. It was badly corroded in the video and in my van. Wires just snapped off when I touched them. You can get to it from underneath, while looking forward.
In the time since I created this thread, I found the bad ground culprit. The clue was in a YouTube video from a mechanic shop. As I remember, he briefly showed a computer screen from an electronic repair manual that showed the location of the ground. It's a ring terminal where several grounds collect near the bottom corner of the radiator on the driver's side (US vehicle). All of these wires are crimped together into the same terminal which is bolted to a vertical surface facing toward the rear of the vehicle. It was badly corroded in the video and in my van. Wires just snapped off when I touched them. You can get to it from underneath, while looking forward.