Turn signals and hazards don't blink

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by herpriusinquirer, Mar 23, 2014.

  1. herpriusinquirer

    herpriusinquirer New Member

    Joined:
    Mar 11, 2014
    9
    0
    0
    Vehicle:
    2004 Prius
    Model:
    N/A
    2004 Prius here. The turn signals and hazard lights stopped working a few days ago. I found a disconnection in the grounding and repaired it. Also replaced the fuse and the flasher switch. Now the lights work, and I can hear the flasher switch clicking, but they don't blink! Any idea what the problem may be here?
     
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    17,557
    5,526
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    Check the 10A HAZ and 10A GAUGE fuses.

    I understand the lights at each corner of the vehicle do not blink, but can be turned on solid. How about the instrument panel, does that show the flashing turn signals when activated?
     
  3. herpriusinquirer

    herpriusinquirer New Member

    Joined:
    Mar 11, 2014
    9
    0
    0
    Vehicle:
    2004 Prius
    Model:
    N/A
    I replaced the HAZ fuse in the engine compartment fuse block (old fuse looked OK though). I don't see a GAUGE fuse there. Is that under dash?

    Flashing does not show on instrument panel. However, all other gauges, etc., seem to be working fine.
     
  4. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    17,557
    5,526
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    Yes, the 10A GAUGE fuse is in the fuse box under the instrument panel, driver's side.

    If that fuse is good, then you will need a digital multimeter and access to the electrical wiring diagram to figure out whether the flasher relay is working correctly.

    What fuse did you previously replace, as described in your OP?
     
  5. herpriusinquirer

    herpriusinquirer New Member

    Joined:
    Mar 11, 2014
    9
    0
    0
    Vehicle:
    2004 Prius
    Model:
    N/A
    OK, I'll have a look at that fuse when I get home.

    I can use multimeter, and I have the diagram of the circuit, but I doubt flasher relay is the problem. I just replaced that on Saturday. Old one seemed dead, and new one clicks like it's supposed to.
     
  6. herpriusinquirer

    herpriusinquirer New Member

    Joined:
    Mar 11, 2014
    9
    0
    0
    Vehicle:
    2004 Prius
    Model:
    N/A
    Fuse previously replaced was HAZ fuse in engine compartment fuse box. But, as I said, the old fuse may not have been blown. Certainly looked OK.
     
  7. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    17,557
    5,526
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    Since you have the diagram of the circuit, you can turn on the hazard switch, and see whether pulsing 12V is present at the flasher relay terminals 2 and 3; or not.

    Use your ohmmeter to verify continuity of the old fuse.
     
  8. herpriusinquirer

    herpriusinquirer New Member

    Joined:
    Mar 11, 2014
    9
    0
    0
    Vehicle:
    2004 Prius
    Model:
    N/A
    OK, thanks, I'll check that. But if I'm not getting correct voltage, then what?
     
  9. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    17,557
    5,526
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    Then see if you have 12V coming into pins 1 and 4 of the flasher relay. Also verify that pin 7 is connected to body ground.

    If you have voltage at the input of the relay, and the relay is making switching noises, but you don't get pulsing voltage at pins 2 and 3, that would imply the relay is not working.
     
  10. herpriusinquirer

    herpriusinquirer New Member

    Joined:
    Mar 11, 2014
    9
    0
    0
    Vehicle:
    2004 Prius
    Model:
    N/A
    OK, thanks! I'll check it a little later and see what I can find out.
     
  11. herpriusinquirer

    herpriusinquirer New Member

    Joined:
    Mar 11, 2014
    9
    0
    0
    Vehicle:
    2004 Prius
    Model:
    N/A
    Well, I was laid out with some health problems for several weeks , but I finally got back to the car and to this problem today.

    12V battery was dead. Parasitic draw from short? Started immediately when jumped though.

    Still no power at any of the turn signal/hazard lamps, front or rear. Upon further inspection I found that the front turn signal bulbs were both badly blown. The sockets also showed signs of being singed. So I replaced them all. The rear lights and sockets looked fine.

    Testing at the flasher relay connection had the following result: pin 1 connector showed around 14 volts, pin 4 connector showed no power at all. So there was of course no pulsing at relay pins 2 & 3. Pln 7 appears to connect to ground.

    Pulled 10A gauge fuse, which looked unblown. Surprisingly to me, this had the effect of bringing on the dreaded red triangle. Replaced fuse and checked, cleaned, and reconnected 12V battery cables. Red triangle gone. Still no power to turn signals.

    Any ideas as to what might be going on here?
     
  12. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    17,557
    5,526
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    "Testing at the flasher relay connection had the following result: pin 1 connector showed around 14 volts, pin 4 connector showed no power at all."
    Check the 10A HAZ fuse again. That provides power to pin 4.

    If the HAZ fuse has blown, before you replace it, measure the resistance from pin 4 to ground. If the resistance is very low, then replace the flasher relay assembly, then replace the HAZ fuse and see if the lights work.

    The GAUGE fuse supplies many circuits, which is why the red triangle master warning light came on, when the fuse was removed.
     
  13. herpriusinquirer

    herpriusinquirer New Member

    Joined:
    Mar 11, 2014
    9
    0
    0
    Vehicle:
    2004 Prius
    Model:
    N/A
    Thank you for the very prompt response!

    One simple question: you keep saying the HAZ fuse should be 10A, and that is what it shows on the wiring diagram. However, on the fuse box cover it shows as a 15A fuse, and what was in place was indeed a 15A fuse, so when I replaced it I put another 15A fuse in. Which should it be?
     
  14. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    17,557
    5,526
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    Replace the fuse according to the markings on the box. Just make sure that the 15A marking corresponds to HAZ and not some other fuse, such as DOME.
     
  15. jeff69dini

    jeff69dini New Member

    Joined:
    Nov 6, 2018
    2
    0
    0
    Location:
    canada
    Vehicle:
    2012 Prius
    Model:
    Four
    similar problem...

    I have no 12V coming into pin 4 of the flasher relay, the fuse was replaced....no change......pin 1 shows 12v fine

    can the hazard switch cause this?
     
  16. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    17,557
    5,526
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    The 10A HAZ fuse is the fuse in question. Pull the fuse and measure resistance across it to make sure the fuse is good. Do not rely upon visual inspection.

    Also, use your voltmeter to measure voltage from body ground to the terminals of that fuse. You should be able to measure 12V from one terminal to body ground.

    If you measure voltage at one terminal of the fuse socket, then insert a good fuse and you do not measure voltage at pin 4 of the flasher relay, then obviously something is wrong with the wiring harness between the fuse box and the flasher relay.

    The hazard switch will ground pin 17 of the flasher relay when it operates. It has no effect on the voltage on pin 4.
     
  17. jeff69dini

    jeff69dini New Member

    Joined:
    Nov 6, 2018
    2
    0
    0
    Location:
    canada
    Vehicle:
    2012 Prius
    Model:
    Four
    thank you so much! looks like it may be the wiring harness after all, how odd for the signal lights/hazards to just stop working 1 minute when it was fine before.............I wonder how the original poster solved his problem?!!
     
  18. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    17,557
    5,526
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    I just noticed you have a G3 model. Pin 8 of the flasher relay is grounded by the hazard switch.

    You could temporarily provide another source of 12V power to pin 4 of the flasher relay, to confirm that the system will work once power is available to that pin. Then, you could run a permanent wire to the relay once you've decided that you can't find a fault in the fuse or the wiring harness upstream from the flasher relay.
     
    Raytheeagle and jeff69dini like this.
  19. SERGEJ GONCARENKO

    SERGEJ GONCARENKO Junior Member

    Joined:
    Mar 6, 2017
    9
    12
    0
    Location:
    IRL
    Vehicle:
    2014 Prius
    Model:
    N/A
    I have very similar problem that occurred after unsuccessful installation if led flasher relay. Two pins of relay got pushed against each other, inside of relay and that caused some reaction. As a result I have no indication or hazard lights.
    Both fuses are not blown, installing original Toyota relay (tried two of them) - didn't bring any results.
    Patrick, Thank you for good ideas, where to look at.
    Now need to find out which pin of relay corresponds to which number ..
    Will share the results as well ..
     
  20. SERGEJ GONCARENKO

    SERGEJ GONCARENKO Junior Member

    Joined:
    Mar 6, 2017
    9
    12
    0
    Location:
    IRL
    Vehicle:
    2014 Prius
    Model:
    N/A
    Cheeked all circuits agan and again, but it was just fuse under the bonnet. That fuse appeared to be good (closed circuit) when checked with multimeter, WHILE IN PLACE. Visually looked good, but I never checked it with multimeter when pulled out of a circuit. That was the cause.
     
Loading...