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Alternator Exciter & Dash Warning Lights

  • 1987
  • 928 S4
120 000
Chilliwack , 
British Columbia

The lesson  learned is to never throw anything out.

Here's the question, I was tidying up the engine bay and found a short rubber hose with a light bulb inside that was hooked up to the alternator exciter (blue wire, pin 13, or 14) in the connector at front passenger side near the engine lift bracket.

I believe this was added by the previous owner (over 20 years ago) and assumed it was for diagnostics or something.

Seemed innocuous enough to remove and tidy up the connection. Also misplaced the hose/bulb apparatus.

Weeks later when the engine bay clean up and drive belts work was finished, the car starts and runs fine.

But hello, the dash indicated no oil pressure (red light on, but gauge reading 5 bar), also voltage gauge reading zero.

Slowly increasing the revs, (or blipping the throttle), will restore the instruments to normal.

I plan to sell the car and it would disconcerting for a buyer to see a no oil pressure light every time he starts the car.

Don't quite understand what is happening and how the removal of the light bulb apparatus is causing this.

Will gladly put the light bulb back where it was but do not know what type or wattage of bulb.

Appreciate any assistance, and have learned not to lose/misplace stuff removed from the car !!!!


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