Turn Signal Problem

Joined
Apr 12, 2021
Messages
55
All I'm trying to do is understand the possible causes and options to fix the problem. Whenever I do repairs, I always start with the simplest possibility first, so of course I'll change the bulb before doing anything else.

If you are sure the signal lamps on the offending side are good, then tracing for good ground is the next thing you should be doing. And it's not at all difficult. If the car in question is the 2011 Camry, it's very possible you could have an issue with the harness ground(s) as a result of age, vibration, or even corrosion.

While I'm not familiar with the Camry's specific harness colors, this info should be easily obtainable online.

The turn signal sockets in question should have three wires: One 12V feed for the parking lamp, one intermittent 12V feed for the signals/hazards, and a ground. The key kicker is to discover which one is the ground (wiring schematic or multi-meter). On my Dodge products, the grounds are black with green or brown stripes. Can't say for Toyota.

The socket wiring undoubtedly disappears into a harness/bundle, which can make specific diagnosis of an individual ground wire quite difficult. However, the bundle itself should have a ground wire emanating from it someplace along the body shell. On my old Caravan, for instance, the front harness ground point is a small stud with a nut on the inner part of the radiator upright. If you follow the socket wires into the harness, and then follow the harness, you'll find the ground point (stud). Make sure the ground wire is intact and it's all clean & shiny metal (not corroded or full of gunk).

In the case of the last one of these I fixed, the ground point was very clean and was therefore of no help. And since the ground wires (right and left side) were buried in a bundle, I really didn't want to start dissecting.

One way to check this theory is to run a separate ground wire to the ground wire of the socket(s) in question. You'll have to peel back a tiny bit of wire insulation and connect a jumper from that point to a clean ground point (I scraped paint from a hidden part of the body behind the headlamp). Once sure you have a good ground, test the bulb and its functions. If it works, you probably have a broken or corroded ground wire (inside the harness).

This sounds wordy and perhaps challenging, but it's not. 1) determine ground wire; 2) check the harness ground point for breakage or corrosion; 3) run a separate ground to the socket in question.

If it's in fact a bad ground wire, just make the jumper wire permanent. Here are some pix from a job I just did to fix this exact issue. I'm not saying this is your problem...but it's a possibility you should investigate nonetheless.

1662906617282.jpeg

1662906638561.jpeg

1662906658366.jpeg

1662906671182.jpeg
 

TCL

Joined
Nov 13, 2020
Messages
293
It's a joke - BMW owners are stereotyped to not use their turn signals.
I see them work occasionally, but not turn in that direction. The driver must bump the stalk with their knee when they are picking their car phone off the passenger side floor.
 

Shel_B

Site Donor 2023
Thread starter
Joined
Aug 7, 2020
Messages
3,217
If you are sure the signal lamps on the offending side are good, then tracing for good ground is the next thing you should be doing.
[...]
Thanks so much for your suggestions and information. I can't imagine a more useful post. Between your post and @wtd's post, I might be able to get this resolved myself. First, a new bulb. Come to think of it, I believe I have some bulbs stashed in the trunk from when I replaced the headlights.
 
  • Like
Reactions: wtd

Shel_B

Site Donor 2023
Thread starter
Joined
Aug 7, 2020
Messages
3,217
Could be bulb. If not, I would think likely ground.

You didn't mention vehicle - I presume the turn signal is handled by something like a BCM, not an old school flasher - correct?
2011 Camry, in my sig.

I haven't a clue about what kind of flasher the car has. Never heard of a BCM ... to me, electricity and wiring is like being dropped into a foreign country without a dictionary.

BCM - some kind of control module?
 
Last edited:

OVERKILL

$100 Site Donor 2021
Joined
Apr 28, 2008
Messages
53,864
Location
Ontario, Canada
2011, in my sig.

I haven't a clue about what kind of flasher the car has. Never heard of a BCM ... to me, electricity and wiring is like being dropped into a foreign country without a dictionary.

BCM - some kind of control module?
BCM = Body Control Module
 
Joined
May 7, 2004
Messages
13,149
Location
Nokesville, VA
Ground problems involving lights at the rear of the vehicle often result in two more bulbs both glowing dimly as the current seeks another path to ground, usually involving another bulb. And they usually cause more than one bulb to not work correctly because several bulbs are all grounded to the same point.

So if, for example, you see your turn signal bulb flashing dimly, and the brake light bulb on that side is also flashing dimly, you can be pretty sure it's a bad ground on that side.
 
Joined
Jul 11, 2015
Messages
7,723
Location
New England
All I'm trying to do is understand the possible causes and options to fix the problem. Whenever I do repairs, I always start with the simplest possibility first, so of course I'll change the bulb before doing anything else.
I just go simple and worry about complications later. Been bug fixing for 30 years developing and now architect of software.
 

JHZR2

Staff member
Joined
Dec 14, 2002
Messages
49,488
Location
New Jersey
Fouled connection at the bulb or harness. They can still illuminate yet flash fast because they’re pulling too little.
 
Joined
Aug 3, 2017
Messages
2,232
Location
MN
I had an issue a couple weeks ago with a mid-00's Caravan and it's LF turn signal/running light. The rear bulb illuminated fine, the front was dim, and there was a hyper-flash on the left. I had good power out of the TIPM to the socket on both the running light and turn signal wires but the ground showed open. I didn't see any obvious damage to the harness in the area, however there was an obvious break in the ground wire between the socket connector and the frame ground.

Since this was an older work van, I chose the easy route: I snipped the GND at the socket, soldered a wire extension to it, and ran said wire directly to the bolt on the NEG battery terminal. Boom, problem solved. Customer didn't care, all he knew was I only charged him $50 for both the diag AND the repair.
 
Joined
Jun 8, 2022
Messages
1,367
2011 Camry, in my sig.

I haven't a clue about what kind of flasher the car has. Never heard of a BCM ... to me, electricity and wiring is like being dropped into a foreign country without a dictionary.

BCM - some kind of control module?
BCM or body control module as mentioned, controls all sorts of electrical things and is solid state instead of an old style mechanical flasher. Typically these flashing fast means one bulb is either burnt out or disconnected - socket, ground, whatever, lowering the resistance in the whole circuit so the remaining light blink faster.
 
Top