Turn signals not workin is not fuse 1989f350pu 460cu

Stop Lamps
The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The body control module (BCM) provides a 5-volt reference voltage and low reference to the brake pedal position sensor. The position sensor provides an analog voltage signal back to the BCM that will increase as the brake pedal is applied. When the brake is applied, the BCM will then apply battery voltage to the left and right stop/turn signal lamp supply voltage circuits and the center high mounted stop lamp (CHMSL) supply voltage circuit illuminating the stop lamps. At the same time the BCM applies battery voltage through the signal circuit to the transmission control module (TCM) and the engine control module (ECM) indicating that the brakes are applied.
Ground for the stop lamps is supplied as follows:
• G402 provides ground for the left rear stop/tail/turn signal lamps
• G403 provides ground for the right rear stop/tail/turn signal lamps
• G301 provides ground for the CHMSL
The stop lamps on this vehicle will not illuminate unless the ignition is in the accessory, run, or crank positions. When the ignition is in the OFF position the stop lamps will not illuminate when the brake pedal is applied.
Battery voltage from the LT TRN/SIG and RT TRN/SIG fuses located in the rear fuse block is also used by the body control module (BCM) for stop lamp operation.

Turn Signal Lamps
Battery voltage supplied to the body control module (BCM) from the fuses listed below is used for turn signal and hazard lamp operation.
• LT TRN/SIG fuse for the left turn signals
• CTSY/RF TRN fuse for the right front turn signal
• RR TRN/SIG fuse for the right rear turn signal
When the turn signal switch is place in either the LEFT or RIGHT position, ground from G300 is applied through the turn signal switch signal circuit to the BCM indicating the turn signal request. In response to this signal, the BCM applies a pulsating voltage to the front and rear turn signal lamps supply voltage circuits cycling the lamps ON and OFF. At the same time the BCM sends a GMLAN serial data message to the instrument panel cluster (IPC) to cycle the appropriate turn signal indicator ON and OFF.
Ground for the turn signal lamps is supplied as follows:
• G104 provides ground for the left and right front turn signal lamps
• G402 provides ground for the left rear stop/tail/turn signal lamps
• G403 provides ground for the right rear stop/tail/turn signal lamps

Do you have a factory scan tool (tech2) ? Your best bet , take it to the dealer .

Service Information
2002 Buick Park Avenue ' Park Avenue (VIN C) Service Manual ' Body and Accessories ' Lighting Systems ' Description and Operation ' Document ID: 643323


Turn Signal/Cornering Lamps
The HZDT/SIG fuse in the fuse block - underhood - left supplies battery positive voltage to the turn signal/hazard flasher module and have ground at G202. The turn signal lamps may only be activated with the ignition switch in the ON or ACCY position. The T/SIG fuse in the fuse block - underhood - left supplies battery positive voltage to the turn signal switch. When the turn signal switch is placed in either the left or right position, current flow is from the turn signal switch assembly to the turn signal/hazard flasher module. The turn signal/hazard flasher module then sends an on-off voltage signal to either the left or right turn signals and their instrument cluster (IPC) indicator. When the hazard switch is pressed, all the turn signal lamps will flash including both IPC turn signal indicators. The left turn signals have ground at G106, G400 and at G402. The right turn signals have ground at G105 and G400. The turn signal switch supplies battery positive voltage to the cornering lamps, the left cornering lamp has ground at G105 and the right cornering lamp has ground at G106.











2002 Buick Park Avenue ' Park Avenue (VIN C) Service Manual ' Body and Accessories ' Lighting Systems ' Description and Operation ' Document ID: 643323

The left an right turn signals get there power from same fuse ,HZDT/SG fuse 15amp in the left under hood fuse box. through the turn signal hazard flasher module. Here is how they work .
Turn Signal/Cornering Lamps
The HZDT/SIG fuse in the fuse block - underhood - left supplies battery positive voltage to the turn signal/hazard flasher module and have ground at G202. The turn signal lamps may only be activated with the ignition switch in the ON or ACCY position. The T/SIG fuse in the fuse block - underhood - left supplies battery positive voltage to the turn signal switch. When the turn signal switch is placed in either the left or right position, current flow is from the turn signal switch assembly to the turn signal/hazard flasher module. The turn signal/hazard flasher module then sends an on-off voltage signal to either the left or right turn signals and their instrument cluster (IPC) indicator. When the hazard switch is pressed, all the turn signal lamps will flash including both IPC turn signal indicators. The left turn signals have ground at G106, G400 and at G402. The right turn signals have ground at G105 and G400. The turn signal switch supplies battery positive voltage to the cornering lamps, the left cornering lamp has ground at G105 and the right cornering lamp has ground at G106.The turn signal switch or the turn / hazard flasher module is bad or there is a wiring problem. Go to you tube an check out a few videos on basic electrical testing ,then get a DVOM - digital volt ohm meter , an wiring diagram an trouble shoot the circuit . There may even be a video on test turn signal circuit .

it's the grounds if they're both flashing fast it's definitely grounds take a test light and see if its got power goes through the test light grounded to the frame and if the light comes on then it's definitely your grounds

Check front and rear lights to see if the wiring is arcing to the turn signal on the left side of the car. This is the best guess as it's simply a wiring problem and nothing else, as there is too much current being forced through the turn signal when the headlights are on. Headlights draw much higher current than the intermittant turn signals and therefore pops the fuse.

I would bet the turn signal lever switch has failed.

the electronic flasher module may be faulty, or you could have blown a fuse

its your blinker box.. all major lights run through there

Rear lights are double filament bulbs one side for the lights other side for the brake/turn signals so it still may be a bulb. Do u have a test light or volt meter you can check to make sure u have power there when brakes or turn signals are activated. Or just try another bulb.

I'd get a 12vdc test light if you don't have one already & start from plug, and keep probing back from there. It may be as simple as a bad connection under truck where joined into harness.