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2005 Ford Focus electrical problem

Ray
I have a 2005 Ford Focus with about 100,000 miles. Problem: when I turn the key off, the dash lights remain on. At times the dash lights will start blinking when the car is running. Also, at times the speedometer will go to zero for about one minute and then return to normal. There is also an alarm under the dash that beeps all of the time. The problem with this is it runs the battery down overnight, the car will not start in the morning without a jump. I know it is an electrical problem, but where does one start? Thanks for any help you can give.
Richard

Ignition switch failure

Its one of 3 items These are in order of repair

  1. Replacing the instrument cluster (most common issue)
    First disconnect and reconnect the cluster several times to clean the connector, oxidation on instrument cluster connectors can cause a poor voltage supply
  2. Alternator connector or Alternator bad should have about 14.4 volts + or - half volt
    While a helper watches the dash, reach behind the engine on the passenger side, and wiggle and twist the alternator connector. Ford calls this a wiggle test, and it is still as good now as it was when it was named. If the dash now behaves properly or gets worse while wiggling, you have found the culprit.
  3. Transmission range switch. Or as it’s PRNDL

That can be one of the early signs of a Body Control Module starting to fail.

https://moduleexperts.com/5-common-symptoms-failing-body-control-module-bcm/

Tester