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Opel Vivaro 1.9 2003 - Absence of Voltage at Fuses in Cabin: Seeking Guidance

mechelek 16779 16
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Why is there no voltage on the first row of cabin fuses in an Opel Vivaro 1.9 (2003), and where should I look for the fault?

The missing voltage on the first cabin fuse row was caused by a faulty UCH (body control unit), which feeds that fuse row; replacing the UCH restored the indicators, hazard lights, cabin lighting and horn [#16938974] [#16951004] If you swap the UCH, the immobilizer may need the old 93c66 EEPROM transferred to the new unit or the immobilizer reworked [#16951577]
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  • #1 16938086
    mechelek
    Level 10  
    Posts: 10
    Rate: 2
    Hello. I am asking for help in the case of Opel vivaro 1.9 2003. PROBLEM: the car happened for a month without an akumlatora - because the car was not needed and the battery was useful for the second van. got offended. directions, horn, emergency and central locking are not working. after checking all fuses (those in the cabin and those under the Majska street), all good and checking the relays (all ticking after connecting the voltage). I took a multimeter and checked the current, and I found out that there is no voltage at all on the 1st row of fuses in the cabin (from the engine side), as shown in the red circle.

    I am asking colleagues for a hint where to look for the perpetrator because I have no idea Opel Vivaro 1.9 2003 - Absence of Voltage at Fuses in Cabin: Seeking Guidance
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  • #2 16938242
    piotrekwoj1
    Level 43  
    Posts: 10332
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    How did you check these relays?
  • #3 16938345
    mechelek
    Level 10  
    Posts: 10
    Rate: 2
    piotrekwoj1 wrote:
    How did you check these relays?


    connect plus to 30 and to 86 and with the minus touch 85, then there is a tension on 87
  • #4 16938650
    rob4028
    Level 25  
    Posts: 621
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    Rate: 470
    The car starts?
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  • #5 16938682
    mechelek
    Level 10  
    Posts: 10
    Rate: 2
    rob4028 wrote:
    The car starts?


    this is how the car starts, drives, etc.

    to the mentioned things that do not work, I forgot to add cabin lighting :)

    Added after 6 [minutes]:

    due to the fact that I have no where (I do not know anyone who has a vivaro to replace) or I do not know how to check if it is operational - today I bought a second UCH controller because I somehow suspect it
  • #6 16938761
    rob4028
    Level 25  
    Posts: 621
    Help: 66
    Rate: 470
    And haven't you thought about the main fuses at the battery ??
  • #7 16938772
    mechelek
    Level 10  
    Posts: 10
    Rate: 2
    rob4028 wrote:
    And haven't you thought about the main fuses at the battery ??


    There is one main fuse on the battery cable - working
    there are functional fuses in the engine compartment.
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  • #8 16938780
    rob4028
    Level 25  
    Posts: 621
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    Rate: 470
    What diagram do you want ???

    Added after 4 [minutes]:

    mechelek wrote:
    there are functional fuses in the engine compartment

    So all the "MAXs" are operational and live?
  • #9 16938802
    mechelek
    Level 10  
    Posts: 10
    Rate: 2
    rob4028 wrote:
    What diagram do you want ???
    Added after 4 [minutes]:
    mechelek wrote:
    there are functional fuses in the engine compartment

    So all the "MAXs" are operational and live?


    so operational and under tension.

    as I remember correctly, one 70A and four 60A (or five)
  • #10 16938827
    rob4028
    Level 25  
    Posts: 621
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    I will ask again ..... What kind of wiring diagrams do you want ... because this is how I can help ... even a lot, if you don't have them ...
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  • #11 16938974
    mechelek
    Level 10  
    Posts: 10
    Rate: 2
    rob4028 wrote:
    I will ask again ..... What kind of wiring diagrams do you want ... because this is how I can help ... even a lot, if you don't have them ...


    diagram where the current goes to the UCH
    and
    where the power goes to the first string of fuses in the cabin
  • Helpful post
    #12 16939002
    rob4028
    Level 25  
    Posts: 621
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    you will get on PW ... ok?




    Moderated By T5:

    3.1.11. Don't post messages that add nothing to the discussion. They are misleading, dangerous or do not solve the user's problem.
    Warning.

  • #13 16951004
    mechelek
    Level 10  
    Posts: 10
    Rate: 2
    I keep fighting. So today the ordered UCH controller came. After connecting the new directions work, emergency ones work. the cabin lighting also works as well as the horn. But I have KU ....... a problem because the car does not start because of the immobilizer - goddamn it.

    and the central one does not work - but stick to his eye (ground with directions) but he could still light up

    A question for colleagues sitting deeper in the car's electrical system - is it possible to disconnect the immo or reprogram the UCH
  • #14 16951577
    piotrekwoj1
    Level 43  
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    Disconnection, no reprogramming, or re-soldering as I'm not mistaken 93c66 from old to new.
  • #15 19676312
    Martin42
    Level 2  
    Posts: 4
    Rate: 1
    Hello, did you fix the fault with the fuses? I found this post and decided to write because I had the same problem and I don't know what to do?
    Thanks in advance for some hint
    Marcin
  • #16 19676381
    pioter488
    Level 15  
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    Start with the shock sensor.
  • #17 19676405
    piotrekwoj1
    Level 43  
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    pioter488 wrote:
    Start with the shock sensor.


    You probably haven't read the topic to the end, or even from the beginning. So the car fired a shock sensor.
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Topic summary

✨ The discussion revolves around a 2003 Opel Vivaro 1.9 experiencing an absence of voltage at the cabin fuses after being without a battery for a month. The user has checked all fuses and relays, confirming they are operational, but found no voltage on the first row of cabin fuses. Suggestions include checking the main fuses at the battery and the wiring diagram for the UCH controller. The user later replaced the UCH controller, restoring functionality to the indicators, emergency lights, cabin lighting, and horn, but encountered issues with the immobilizer preventing the car from starting. Further advice was sought on disconnecting or reprogramming the immobilizer.
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FAQ

TL;DR: On a 2003 Opel Vivaro 1.9, loss of indicators/hazards/horn/central light often traces to the cabin fuse feed from MAXI fuses—"one 70A and four 60A"—so verify power to the first fuse row and the UCH first. [Elektroda, mechelek, post #16938802]

Why it matters: This FAQ helps DIYers quickly restore dead cabin circuits and avoid immobilizer pitfalls after a UCH swap on Vivaro/Trafic/Primastar vans.

Quick Facts

How do I diagnose no voltage on the first row of cabin fuses?

Confirm battery health, then probe both sides of each fuse in row one with ignition on. Back‑trace from under‑bonnet MAXI fuses to the cabin block. Verify continuity and feed to the UCH. If upstream fuses are live but the cabin rail is dead, suspect the UCH or its supply connector. Document readings and wiggle‑test harness sections between bay and cabin. This mirrors the thread’s initial finding of a dead first row despite good engine‑bay fuses. [Elektroda, mechelek, post #16938086]

What is the UCH on a Vivaro?

UCH is the body control module that distributes power and logic for indicators, hazards, horn, interior lighting, and central locking. Loss of its feed or internal failure can kill those circuits while the engine still runs. The original poster sought diagrams for UCH power paths, underscoring its central role in cabin electrics. [Elektroda, mechelek, post #16938974]

Could the engine still start if indicators, horn, and hazards are dead?

Yes. In the discussed case the van started, drove, and only body functions were down. That points to a body/control feed issue rather than engine management. This separation helps you avoid chasing ECU or fuel faults when the symptom set is purely cabin systems. [Elektroda, mechelek, post #16938682]

Which high‑current fuses feed the cabin board on this model?

The user confirmed an under‑bonnet set of MAXI fuses: one 70A and four 60A. These supply downstream cabin circuits, including the first fuse row. Inspect for voltage presence, not just continuity, and load‑test if necessary. “One 70A and four 60A” was noted during troubleshooting. [Elektroda, mechelek, post #16938802]

Is the main battery fuse the likely culprit here?

It can fail, but in the thread the main battery fuse and engine‑bay fuses tested OK while the first cabin row had no voltage. That steers diagnosis toward the UCH feed or the harness segment between the bay and the cabin fusebox. [Elektroda, mechelek, post #16938772]

What immediate fix restored the dead cabin functions in the thread?

Swapping in another UCH brought back indicators, hazards, horn, and interior lighting. This confirmed the original UCH or its data as the root cause for dead cabin circuits, though a start‑inhibit then appeared due to immobilizer pairing. [Elektroda, mechelek, post #16951004]

Why didn’t the van start after installing a replacement UCH?

The immobilizer data in the UCH didn’t match the vehicle. After replacement, the van’s body functions returned but the immobilizer blocked starting until data was migrated or paired. This is a typical outcome after a control unit swap without key/EEPROM transfer. [Elektroda, mechelek, post #16951004]

How do I make a replacement UCH start the van?

Move the immobilizer data. The forum guidance: reprogram or re‑solder the 93C66 EEPROM from the old UCH to the new one. As the expert put it, “Disconnection, no reprogramming,” meaning don’t try to bypass IMMO—transfer data correctly. [Elektroda, piotrekwoj1, post #16951577]

Could a shock or crash sensor cause these symptoms?

No, not when the engine starts. A respondent noted the car started, so focus on UCH supply and cabin feed rather than crash/shock sensors. Chasing those will waste time if the power rail to the cabin fuses is the real issue. [Elektroda, piotrekwoj1, post #19676405]

What’s a quick 3‑step check to isolate the fault?

  1. Verify live voltage at each MAXI fuse (70A/60A) under the bonnet.
  2. Probe both blades of each fuse in the first cabin row for 12V.
  3. If cabin row is dead but MAXIs are live, inspect UCH feed connector and swap‑test UCH (mind immobilizer). [Elektroda, mechelek, post #16938802]

Does leaving the van without a battery trigger these issues?

In the case discussed, the van sat about a month without a battery before symptoms were noticed. That context suggests corrosion, memory loss, or UCH stress might manifest afterward. Use it as a clue during history taking. [Elektroda, mechelek, post #16938086]

How should I test relays correctly when chasing body power faults?

Bench‑energize with 12V across coil terminals (e.g., 85/86) and confirm switched continuity on 30–87 under load. The OP used this method to verify ticking and output. Always load‑test; a relay can click yet fail under current. [Elektroda, mechelek, post #16938345]

What if all MAXI fuses are live but the first cabin row is still dead?

Then the failure lies in the feed path or UCH. Check the harness from engine bay to cabin, connector corrosion, and UCH internal faults. The thread’s turning point was acknowledging live MAXIs yet a dead cabin row, leading to UCH action. [Elektroda, mechelek, post #16938802]

What is a CAN bus?

CAN bus is the two‑wire network that lets modules like the UCH and ECU communicate. A dead power feed can mimic CAN faults by silencing modules. Restore clean power first, then investigate communications if symptoms persist. [Elektroda, mechelek, post #16938974]

Any edge cases to watch out for after a UCH swap?

A start block from immobilizer mismatch is normal after swapping UCHs. Until you migrate 93C66 data, the engine won’t crank or run despite restored body functions. Plan EEPROM work before concluding the repair. [Elektroda, mechelek, post #16951004]

Which wiring info should I request or print before testing?

Get the feed diagram from battery/MAXI to cabin fuse row and the UCH power/ground pinout. Those two views guided the original poster’s next steps and will accelerate your tracing. [Elektroda, mechelek, post #16938974]
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