Injection control unit voltage

- M
- Mungo "Two Sheds" Toadfoot
  
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posted
17 years ago

Fri, Aug 25, 2006 10:40 AM

Does anyone know what voltage ICUs work on?

'Er Micra's reverse light switch doesn't work and it also has a second function which is to indicate neutral to the ICU. There's no continuity in the switch(es) when the car's in neutral or reverse so it/they must be buggered.

I tested for voltage on one side of the input to the switch(es) and there's

12v on one pin, which I'm assuming is for the reverse light, but only 4.6v on the other, neutral, pin so I wondered if ICUs work on 5v perhaps? I hope so because otherwise I'm into 'lectric fettling and I don't like 'letrics.

Si

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- Coyoteboy
  
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posted
17 years ago

Fri, Aug 25, 2006 12:22 PM

Internally they work on 5v and some external sensors also run 5v but i would have thought a straighforward switch would have been a 12v thu. Without the wiring diagram i cant be more specific im afraid.

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- Peter Hill
  
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posted
17 years ago

Fri, Aug 25, 2006 4:11 PM

Neutral switch pulls down to earth.

4-5v is correct when ign is on and not in neutral. 0v when in neutral and ign on.

Reverse has 12v feed to switch when ign is on. If you don't get 12v on other side of switch when in reverse then switch is faulty. If you do get 12v on both wires from switch but no reversing lamp then bulb or wiring fault.

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- Mungo "Two Sheds" Toadfoot
  
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posted
17 years ago

Sat, Aug 26, 2006 3:56 PM

Thank you kindly.

There's voltage at both feed pins of the connector plug when the ignition's on but when I test the other half of the connector there's no continuity in either the neutral or reverse switches, when in neutral or reverse obviously. Seems odd that they've both failed but I haven't taken it out to see how it works because the gear oil will fall out :)

Si Si