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Fiero Headlamp Gen 1 - help with test results

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  • Fiero Headlamp Gen 1 - help with test results

    Hello – I am looking for input on fiero first gen headlight troubleshooting that i did.
    I went through the troubleshooting video (Buddy's video in below link) and need to confirm if it is the isolation switch or test motor relay.
    I have posted two questions below.

    1) Test for headlight switch.
    - White wire (headlight switch OFF): measures 12V and also tested with test light and comes on.
    - Yellow wire (headlight switch ON): measures 10.5V (instead of 12V) and test light comes on.
    Question1 – is the 10.5V an issue?

    2) Testing motor – isolation switch
    a)Test motor - make it go up
    White wire – plug it into pink wire – both sides of motors should go up - PASS

    b)Test motor - make it go down
    Plug White wire - blue white stripe will make passenger side go down - PASS
    Plug White wire – to solid blue wire will make driver side go down - FAIL

    3) Test motor relays:
    I tested the driver side that failed.
    Test to make motor go up: Green wire on motor side and link with red wire: PASS
    Test to make motor go down: Black to Green and Blue wire with Red: PASS
    Question 2: If the motor goes up when I bypass motor relay switch, does that mean the motor relay is bad or the isolation switch is bad?

    This is the link to Buddy’s video that I followed:

  • #2
    In case others have similar issues and reading this post, I have received a response on one of the other boards and they stated it was most likely the isolation switch. I will be looking to purchase from Rodney or a good used one to see if it addresses the issue and will post here.


    • #3
      Fiero Headlamp Gen 1 help with test results

      Does your meter have a setting for continuity? Continuity and Ohms are not the same. Presuming that you have a setting for continuity, I would start at the headlight plug. Put one lead on a good solid ground the green wire connecting to the coils is a good one thats close to the light and put the other on the end of the blue wire at the plug. Your meter should tell you immediately if you have continuity with ground not good or not. When you say, "since I knew the headlight fuse went out, I started from there and back tracked through every section of wire," What do you mean? Where did you start? At the fuse? And when you "back tracked" were you going back down the harness towards the battery?


      • #4
        Hi KamGils - I will try the continuity test. I had to take a break from the project due to frustration lol.
        For the 2nd question, i started to measure the voltages at the isolation switches without checking all the fuses first.
        When I checked the fuses, the headlight fuse was blown (rookie mistake).
        It will be interesting to see what the continuity test reveals.
        One of the feedback on the other boards stated the low voltage could be due to high current load from a component.
        I will post a response once i complete the test.
        Thank you for the feedback.


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