TURN SIGNAL - 1999 Toyota Sienna

Possibly bad ground connection - G100
In back of the right headlamp on the frame. Headlamps, turn signals, parking lamp for the right all ground at that point. Corrosion in the wire, broken park lamp wire.
Headlamps, turn signals, parking lamp all have their own ground wire that connects at that point.

Hooking up a professional grade scan tool an check for DTC'S - diagnostic trouble codes in the BCM - body control module may point in a diagnostic direction.

DTC B3949: Right Front Turn Signal
Right Front Park/Turn Signal Inoperative

Circuit/System Description
The Body Control Module (BCM) controls the turn signals based on an input from the turn signal switch, part of the multifunction turn signal lever. The BCM receives an input from one of two signal circuits to determine which turn signal function is requested. When the turn signal lever is placed in the LEFT position, the left turn signal switch signal circuit is grounded indicating that left turn signal operation is requested. When the turn signal lever is placed in the RIGHT position, the right turn signal switch signal circuit is grounded indicating that right turn signal operation is requested.
When a turn signal input is received from the turn signal switch, the BCM will activate the appropriate turn signals. The BCM pulses voltage to the applicable turn signals via the turn signal lamp supply voltage circuits, illuminating the required turn signal lamps.

B3949
A short to voltage, short to ground, or an open/high resistance is seen on the right front turn signal lamp supply voltage circuit.

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Turn Signal Lamps
The STOP/TURN/HAZARD fuse in the instrument panel (I/P) fuse block supplies battery positive voltage to the body control module (BCM) for the turn signal lamps. When the turn switch is placed in the LEFT TURN or RIGHT TURN position, ground is applied from G202 through the turn switch, to the turn signal switch signal circuit and to the BCM. The BCM then applies battery positive voltage to front and rear turn signal lamps supply voltage circuits. The left front turn signal lamp is grounded at G100, right front at G101, left rear at G301 and the right rear is at G302.

Turn Signal Reminder
The driver information center (DIC) activates the turn signal warning as requested by either turn signal switch. The turn signal warning sounds when the following occurs:
• The ignition is in RUN.
• The turn signal switch is in either turn position, sensing, within 1 second, an open to battery positive voltage transition in the turn signal control circuit, left or right turn.
• The vehicle has traveled a distance of 1.2 km (0.75 mi) by counting pulses in the rolling odometer class 2 message.
The DIC turns OFF the turn signal reminder when either the ignition switch is turned to the OFF position, or the turn signal switch returns to the OFF position, sensing within 1 second, no transitions from open to battery positive voltage in either of the turn signal control circuits, left turn or right turn.

My first step would be to hook up a factory scan tool an check for DTC'S - diagnostic trouble codes

DTC B3948 Left Front Turn Signal Circuit
Circuit Description
Ground is applied to the turn signal switch. When the turn signal switch is placed in the turn left position, ground is applied to the body control module (BCM) through the left turn signal switch circuit. The BCM then applies a pulsating voltage to the LF and LR turn signal lamps through the LF and LR turn signal voltage supply circuits.

What's the left rear lamp doing ? Flashing fast ?

DTC B3950 Left Rear Turn Signal Circuit

Probably the bulb or wiring harness to the door where it bends when you open and shut the door.

The turn signal lamps may only be activated with the ignition switch in RUN or BULB TEST position. The T/SIG fuse supplies ignition voltage to the turn signal switch. When the turn signal switch is placed in either the left or right position, the turn signal switch sends an ignition voltage to the hazard lamp/turn signal flasher, which sends an on-off signal to the turn signal switch. When the turn signal switch receives the on-off signal it will send that signal to the following lamps on the LH or RH side:
• The Rear Turn Lamp
• The Turn Signal Indicator
• The Sidemarker Lamp
• The Sideview Mirror (Pontiac Thunder only)
The turn signal switch also sends a separate on-off signal to the Daytime Running Lamps (DRL) control module, which relays the signal to the appropriate front turn signal. The front turn signals are grounded at G101 and G102. The rear turn signals are grounded at G401. The sidemarker lamps are grounded through the corresponding front parklamp.
The sideview mirror turn signals are a bank of LEDs placed behind the mirror glass.
The hazard lamps operate on battery voltage. The HAZARD fuse supplies battery voltage to the turn signal switch. When the hazard switch is pressed, the turn signal switch sends battery voltage to the hazard lamp/turn signal flasher, which sends an on-off signal to the turn signal switch. The turn signal switch send the on-off signal to all the turn signal lamps, causing all the lamps to flash including both IPC turn signal indicators. The hazard lamp/turn signal flasher is grounded at G200.
When the parklamps are ON, the sidemarker lamps receive voltage from the park lamp supply voltage circuit and illuminate. The sidemarker lamp is grounded through the corresponding rear turn signal. When the turn signal switch is place in the left or right hand position, the rear turn signal illuminates and the sidemarker lamp will loose its ground, causing the sidemarker lamp to turn off when the turn signals are on and to illuminate again when the turn signal is off.

Turn Signal Lamps
The FRT/TRN/HAZ/CRTSY/MIRR and REAR/TRN/HAZ fuses in the underhood fuse block supplies battery positive voltage to the body control module (BCM). When the turn signal switch is placed in either the left or right position, a signal is sent to the BCM to illuminate the desired turn signal lamps. The BCM has an internal flasher that sends an ON-OFF voltage signal to either the left or right turn signals and their instrument panel cluster (IPC) indicator. When the hazard switch is pressed, a separate ground signal is sent to the BCM to activate and flash all turn signal lamps including both IPC turn indicators. The front and rear turn signals are grounded at G105, G350 and G340. The sound for the turn signal indicators is produced by the IPC.

DTC B0525 Left Turn Signal Circuit
• DTC B0527 Right Turn Signal Circuit Low
• DTC B0528 Right Turn Signal Circuit High
• DTC B0529 Right Turn Signal Circuit Open
DTC B0530 Right Turn Signal Circuit
• DTC B0532 Left Turn Signal Circuit Low
• DTC B0533 Left Turn Signal Circuit High
• DTC B0534 Left Turn Signal Circuit Open
Could be a switch problem , short to ground on the signal circuit to the BCM , BCM seeing a input that shouldn't be there etc....
I would have it checked for DTC'S diagnostic trouble codes .

What fuse are you pulling ?

Hazard Lamps
The hazard warning switch is part of the turn signal switch. The turn signal switch receives battery voltage at all times through the HAZARD SWITCH Fuse. When the hazard switch is placed in the HAZARD position, battery voltage is applied to the hazard lamp/turn signal lamp flasher. The hazard lamp/turn signal lamp flasher sends a turn signal flasher signal to the turn signal switch. The turn signal switch provides all of the turn lamps and turn indicators with the turn signal flasher signal, simultaneously flashing them on and off.

Turn Signal Lamps
The front turn signal lamps are made up of the front park/turn signal lamps and rear turn signal lamps. The front turn signal lamps flash with the rear turn signal lamps when a turn is initiated using the turn signal/multifunction lever. The turn signals will operate only with the ignition switch in the RUN position and will not operate during hazard flasher operation.
When the ignition is turned to the RUN position, battery voltage is supplied to the TURN SIGNAL Fuse. Battery voltage is then applied through the turn signal fuse circuit to the turn signal switch. When the turn signal switch is placed in the LH or RH position, voltage is supplied to the hazard lamp/turn signal lamp flasher. The hazard lamp/turn signal lamp flasher supplies a turn signal flasher signal to the turn signal switch. With the turn signal switch in the LH or RH position the corresponding turn signal indicator, rear turn signal, and front turn signal receive the turn signal switch signal and will flash. The front turn signals receive the turn signal switch signal from the turn signal switch via the BCM. The turn lamps are permanently grounded.

Replace the turn signal switch. Refer to Multifunction, Turn Signal, and Hazard Switch Replacement - On Vehicle in Steering Wheel and Column - Tilt.

Turn Signal Lamps
The turn signal lamps may only be activated with the ignition switch in RUN or BULB TEST position. The T/SIG fuse supplies ignition voltage to the turn signal switch. When the turn signal switch is placed in either the left or right position, the turn signal switch sends an ignition voltage to the hazard lamp/turn signal flasher, which sends an on-off signal to the turn signal switch. When the turn signal switch receives the on-off signal it will send that signal to the following lamps on the LH or RH side:
?€¢
The Rear Turn Lamp

?€¢
The Turn Signal Indicator

?€¢
The Sidemarker Lamp

?€¢
The Sideview Mirror (Pontiac Thunder only)

The turn signal switch also sends a separate on-off signal to the Daytime Running Lamps (DRL) control module, which relays the signal to the appropriate front turn signal. The front turn signals are grounded at G101 and G102. The rear turn signals are grounded at G401. The sidemarker lamps are grounded through the corresponding front parklamp.
The sideview mirror turn signals are a bank of LEDs placed behind the mirror glass.
The hazard lamps operate on battery voltage. The HAZARD fuse supplies battery voltage to the turn signal switch. When the hazard switch is pressed, the turn signal switch sends battery voltage to the hazard lamp/turn signal flasher, which sends an on-off signal to the turn signal switch. The turn signal switch send the on-off signal to all the turn signal lamps, causing all the lamps to flash including both IPC turn signal indicators. The hazard lamp/turn signal flasher is grounded at G200.
When the parklamps are ON, the sidemarker lamps receive voltage from the park lamp supply voltage circuit and illuminate. The sidemarker lamp is grounded through the corresponding rear turn signal. When the turn signal switch is place in the left or right hand position, the rear turn signal illuminates and the sidemarker lamp will loose its ground, causing the sidemarker lamp to turn off when the turn signals are on and to illuminate again when the turn signal is off.
Which blub an socket did you replace ? check the other blub ? The switch and or the flasher module can cause this problem .
Replace the turn signal switch. Refer to Multifunction, Turn Signal, and Hazard Switch Replacement - On Vehicle in Steering Wheel and Column.
Did you complete the replacement?

Which

Turn Signal Lamps
The turn signal lamps are made up of the front park/turn signal lamps and rear turn signal lamps. The front turn signal lamps flash with the rear turn signal lamps when a turn is initiated using the turn signal/multifunction lever. The turn signals will operate only with the ignition switch in the RUN position and will not operate during hazard flasher operation.
When the ignition is turned to the RUN position, battery voltage is supplied to the TURN SIGNAL, CORN LPS Fuse. Battery voltage is then applied through the TURN SIGNAL, CORN LPS fuse circuit to the hazard warning switch. The hazard switch supplies a turn signal flasher signal to the turn signal switch. With the turn signal switch in the LH or RH position the corresponding turn signal indicator, rear turn signal, and front turn signal receive the turn signal switch signal and will flash. The front turn signals receive the turn signal switch signal from the turn signal switch via the body control module (BCM) . The front turn lamps are grounded at G101. The rear turn lamps are grounded at G301 and G302.
Turn Signal Lamps and/or Indicators Inoperative

2

1. Turn the ignition switch to the ON position.
2. Place the turn signal switch in the LH and RH on position.

Do the turn signals operate properly?
Go to Testing for Intermittent Conditions and Poor Connections yes
Go to Step 3 no

3

Are all of the turn signal lamps and indicators inoperative?
Go to Step 5 yes
Go to Step 4 no

4

Are only the turn signal indicators inoperative?
Go to Step 16 yes
Go to Step 9 no

5

Check the TURN SIGNALS CORN LPS fuse for an open.
Is the TURN SIGNALS CORN LPS fuse open?
Go to Step 25 yes
Go to Step 6 no

6

1. Disconnect the hazard switch.
2. Turn the ignition to the ON position, with the engine OFF.
3. Connect a test lamp between the ignition positive 1 voltage circuit of the hazard switch and a good ground.

Does the test lamp illuminate?
Go to Step 7 yes
Go to Step 27 no

7

Connect a test lamp between the ignition 1 positive supply voltage circuit of the hazard switch and the ground circuit of the hazard switch .
Does the test lamp illuminate?
Go to Step 8 yes
Go to Step 23 no

8

1. Install a fused jumper between the ignition 1 positive voltage circuit of the hazard switch and the turn signal flasher signal circuit of the hazard switch.
2. Place the turn signal switch in the RH on position and the LH on position.

Do the turn signal lamps illuminate?
Go to Step 17 yes
Go to Step 15 no

9

Is a front turn signal inoperative?
Go to Step 10 yes
Go to Step 13 no

10

1. Turn the ignition switch to the ON position.
2. Disconnect the inoperative front turn signal lamp.
3. Connect a test lamp between the supply voltage circuit of the inoperative front turn signal lamp and a good ground.
4. Place the turn signal switch in the appropriate ON position.

Does the test lamp flash ON and OFF?
Go to Step 14 yes
Go to Step 11 no

11

1. Disconnect the body control module (BCM) connector.
2. Connect a test lamp between ground and the front turn signal switch signal circuit of the BCM.
3. Place the turn signal switch in the appropriate ON position.

Does the test lamp flash ON and OFF?
Go to Step 12
Go to Step 22

12

Test for an open or for a high resistance in the supply voltage circuit of the inoperative front turn signal lamp. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?
Go to Step 34
Go to Step 21

13

1. Turn the ignition switch to the ON position.
2. Disconnect the inoperative rear turn signal lamp.
3. Connect a test lamp between the supply voltage circuit of the inoperative turn signal lamp and a good ground.
4. Place the turn signal switch in the appropriate ON position.

Does the test lamp flash ON and OFF?
Go to Step 14
Go to Step 28

14

Connect a test lamp between the ground circuit of the inoperative turn signal lamp and supply voltage circuit of the inoperative turn signal lamp.
Does the test lamp illuminate?
Go to Step 20
Go to Step 26

15

Test for an open or high resistance in the turn signal flasher signal circuit. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?
Go to Step 34
Go to Step 18

16

1. Turn OFF the ignition.
2. Disconnect the instrument panel cluster (IPC).
3. Connect a test lamp between the supply voltage circuit of the inoperative turn signal indicator and the instrument panel cluster (IPC) ground circuit.
4. Place the turn signal switch in the appropriate ON position.

Does the test lamp flash ON and OFF?
Go to Step 19
Go to Step 24

17

Inspect for poor connections at the harness connector of the hazard switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?
Go to Step 34
Go to Step 30

18

Inspect for poor connections at the turn signal switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?
Go to Step 34
Go to Step 29

19

Inspect for poor connections at the instrument panel cluster (IPC). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?
Go to Step 34
Go to Step 31

20

Inspect for poor connections at the inoperative turn signal lamp. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?
Go to Step 34
Go to Step 32

You don't have fire , never heard it called that before ! Battery voltage , power but never fire ! An open CTSY fuse located in the I/P fuse block will affect the operation of the right front turn signal only
Turn Signal/Hazard Lamps When the turn signal switch is placed in either the left or right position, a ground signal is completed from the turn signal switch to the BCM. When the hazard flasher switch is activated, a ground signal is completed from the turn signal/hazard switch to the BCM. The BCM then sends an ON-OFF voltage signal through the fuses to the appropriate turn signal and side repeater (export only) lamps or to all of the turn signal fuses for hazard operation. The driver door switch and passenger door switch also receive voltage from the BCM turn signal supply voltage circuits for the mirror turn signals. The door switches have no function or control of the mirror turn signals other than a pass through connection for the circuits. The audio chime is also activated when the turn signals are ON. The instrument panel cluster (IPC) receives the signals to activate the turn signal indicators over the GMLAN serial data system. When the hazard switch is pressed, all turn signal lamps will flash including both IPC turn indicators.
Ground is applied at all times at G201 to the turn signal/multifunction switch. The turn signal lamps may only be activated with the ignition switch in the ON or START position. When the turn signal/multifunction switch is placed in either the TURN RIGHT or TURN LEFT position, ground is applied to the body control module (BCM) through either the right turn or left turn signal switch signal circuit. The BCM then applies a pulsating voltage to the front and rear turn signal lamps through their respective control circuits.
.

Here is what the service manual says. Looks like it is not a flasher relay but a function of the body control module.

TURN SIGNAL AND HAZARD WARNING LAMP SYSTEMSystem Description OUTLINE Turn signal lamp and the hazard warning lamp is controlled by combination switch reading function and the flasher control function of BCM.
TURN SIGNAL LAMP OPERATION - BCM detects the combination switch condition by the combination switch reading function. - BCM supplies voltage to the right (left) turn signal lamp circuit when the ignition switch is turned ON and the turn signal switch is in the right (left) position. BCM blinks the turn signal lamp.
HAZARD WARNING LAMP OPERATION BCM supplies voltage to both turn signal lamp circuit when the hazard switch is turned ON. BCM blinks the hazard warning lamp.
TURN SIGNAL INDICATOR LAMP AND TURN SIGNAL SOUND OPERATION - BCM transmits the turn indicator signal to the combination meter with CAN communication while the turn signal lamp and the hazard warning lamp are operating. - Combination meter outputs the turn signal sound with the integrated buzzer while blinking the turn signal indicator lamp according to the turn indicator signal.
HIGH FLASHER OPERATION (FAIL-SAFE) - BCM detects the turn signal lamp circuit status by the terminal current value. - BCM increases the turn signal lamp blinking speed if the bulb or harness open is detected with the turn signal lamp operating. NOTE: The blinking speed is normal while operating the hazard warning lamp.