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Error code reference

Dacor Oven Error Code C78

Light error

Dacor codesDacor oven codes
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What the C78 error code actually means

Your Dacor oven is detecting that the electrical voltage powering its interior lighting system has dropped too low to work correctly. This is typically caused by a failing LED light board or a problem with the oven's main control board. The oven flags this to let you know the lighting circuit needs attention, and it usually requires replacing one of those two components to fix.

Diagnostic procedure

The full C78 procedure

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1
First diagnostic step
Replace LED board. If LED board replacement did not resolve issue, replace logic board.
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Most common causes of C78

Ranked by how often they cause this code
  1. 1Failed LED Board
  2. 2Logic Board Voltage Output Failure
  3. 3Wiring or Connector Issue Between Logic Board and LED Board
  4. 4Intermittent LED Board Connection

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Questions people ask about C78

What does C78 mean on a Dacor oven?
C78 on a Dacor oven means the voltage supplying the LED lighting board has dropped below 15V. The oven's control system monitors this voltage level and triggers the C78 code when it falls below the required threshold. This fault points to either the LED board or the logic board as the source of the problem.
Is it safe to use my Dacor oven while it shows error code C78?
C78 is a lighting circuit fault and does not directly affect the oven's heating or cooking functions. However, operating an appliance with a known electrical fault is not recommended without understanding the full scope of the issue. It is best to have the fault diagnosed and repaired before continued regular use.
How much does it cost to repair a Dacor oven showing C78?
Repair costs depend on which component is at fault. LED board replacement parts typically range from around $50 to $150, while a logic board can range from $150 to $400 or more depending on the model. Adding professional labor, total repair costs can range from $150 to $600 or higher depending on the technician and parts required.
Can I fix C78 on my Dacor oven myself?
A knowledgeable DIYer can attempt this repair by starting with an LED board replacement, which is the first recommended diagnostic step. If that does not resolve the code, the logic board must also be replaced. Both repairs involve working inside the oven's electrical system, so anyone uncomfortable with appliance electrical work should contact a qualified technician.
Will resetting my Dacor oven clear the C78 error code?
A power reset may temporarily clear the C78 code, but the fault will return if the underlying component failure is not repaired. The LED board or logic board must be addressed to permanently resolve the undervoltage condition causing the error.

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