How does the speedomter work?
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Senior Member
Joined: Jan 2001
Posts: 311
Likes: 1
From: Atlanta, GA USA
How does the speedomter work?
Does an increasing + voltage make the needle move higher as speed increases or does the ground to the speedometer change?
Does the ECU control the speedomter or is their a secondary "computer" that controls it?
Thanks.
Does the ECU control the speedomter or is their a secondary "computer" that controls it?
Thanks.
Senior Member
Joined: Aug 2000
Posts: 243
Likes: 0
From: Palm Beach County, FL
Copied this from the Ford Service Manual Theory of Operation:
"The instrument cluster (10849) receives the vehicle speed signal from the powertrain control module (PCM) (12A650) over the SCP network and displays it on the speedometer gauge. If the instrument cluster receives no vehicle speed signal after one second, the speedometer defaults to 0.0 km/h (0.0 mph)."
Sorry I can't add more to the terse verbage.
XLT_D
"The instrument cluster (10849) receives the vehicle speed signal from the powertrain control module (PCM) (12A650) over the SCP network and displays it on the speedometer gauge. If the instrument cluster receives no vehicle speed signal after one second, the speedometer defaults to 0.0 km/h (0.0 mph)."
Sorry I can't add more to the terse verbage.
XLT_D