Gremlins have invaded my Lt. rear turn signal

[olddude]

Lt. rear turn signal will not work, every thing else works, tail light, brake and back up. Front left light just burns steady when selected. All other lights work correctly. I checked all the bulbs and replaced flasher relay. no help.

[Ωhm]

3 hours ago, olddude said:

Front left light just burns steady when selected.

This one makes me wonder.

 

 

KEY OFF. Depress Brake pedal. Using the Turn Signal SW (L/R) can you TURN OFF each sides brake light? This will check a couple of the TS switches.

[ghetdjc320]

If the test above checks out, try checking the bulb sockets, and use new bulbs even if they look good. 

[Eagle_SX4]

Have you checked the condition of the bulb sockets? Any visible corrosion? When I got my truck the front turn signal sockets were corroded and didn't work correctly. Maybe the sockets are to blame? I cut the old ones off and soldered in some "new" ones from the junkyard and everything is working great now.

[gogmorgo]

Hazards and brake lights work fine on that corner, just not the turn signal?

You haven’t swapped to LEDs have you? Checked the bulbs were correct for the location?
A conventional flasher unit will stay solid if there’s not enough load on it. 

First step is to check for power and ground at the socket. Use a test light, not a multimeter. You can check a ground with the test light by clamping to a power source and probing the ground contact.
 

[olddude]

20 hours ago, Ωhm said:

This one makes me wonder.

 

 

KEY OFF. Depress Brake pedal. Using the Turn Signal SW (L/R) can you TURN OFF each sides brake light? This will check a couple of the TS switches.

I was wrong. The Lt brake light does not work either. I tried different bulbs around and no help. The Rt turn signal  will turn the Rt brake light off.

sockets look fine, just a little dirty. Have not changed to LED bulbs. 

[Ωhm]

Disconnect C157. Look for Brake or TS voltage on IC harness side of C157_E. If you get voltage problem lies towards TS sockets, if NO voltage, problem lies towards TS SW.

 

 

[olddude]

Thanks Ohm, I will check it out.

[olddude]

Okay there must be a gremlin in light wiring. It keeps changing. Here's what I have done yesterday and today..........I replaced all the bulbs, rechecked to sockets, checked all the fuses and replaced the flasher relays.

Everything up front works, the parking lights, head lights and turn signals. Nothing in the rear works. I guess I have to get to that C157 connector.

[gogmorgo]

Do you have power at the socket when you should? Ground?

 

No sense diving through your entire wiring harness when you don’t know what side of the circuit has the problem, and poking around in places you don’t know to be a problem is likely to create a new problem to solve.
Nothing on either side in the rear working strongly suggests a ground issue. The taillight harness grounds to a sheet metal screw behind the driver’s taillight. That or some fuses got popped. 
If you don’t have power, the connector between taillight harness and the truck, on the frame behind the driver’s rear wheel, is the next place I would look. 

 

[olddude]

50 minutes ago, gogmorgo said:

Do you have power at the socket when you should? Ground?

 

No sense diving through your entire wiring harness when you don’t know what side of the circuit has the problem, and poking around in places you don’t know to be a problem is likely to create a new problem to solve.
Nothing on either side in the rear working strongly suggests a ground issue. The taillight harness grounds to a sheet metal screw behind the driver’s taillight. That or some fuses got popped. 
If you don’t have power, the connector between taillight harness and the truck, on the frame behind the driver’s rear wheel, is the next place I would look. 

 

No power to the rear lights. The ground checks good.

[Ωhm]

On 10/25/2023 at 11:06 AM, olddude said:

I guess I have to get to that C157 connector.

 

Instead of disconnecting C157, pick up a testlamp, find a good ground and just stick the wire (C157_E). Tape the poked hole when done.

 

 

[gogmorgo]

Don’t puncture your wiring insulation on the vehicle exterior if you like having wires inside it. Tape doesn’t stop moisture getting in, it just prevents it from drying back out when it inevitably does get in. 

[Eagle_SX4]

I have actually had the wires break off at the brake pedal switch twice now. Double check for broken wires on the brake pedal switch.

[olddude]

On 10/27/2023 at 8:02 PM, Ωhm said:

 

Instead of disconnecting C157, pick up a testlamp, find a good ground and just stick the wire (C157_E). Tape the poked hole when done.

 

 

 

[olddude]

I have a test lamp, been using it. I unplugged cable going to rear lights just behind the left wheel well. Nothing at all there. I checked for voltage at the head light switch and have voltage at there. haven't found the  C157. found a connector in that area that has 8 wires, no power.