PSOM help
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Joined: May 2014
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PSOM help
I have a 1992 F250. The speedometer/odometer were not working so I replaced the PSOM. The new one did not work either. The fuses in the dash are good. I checked the plug and I have volts in pin 4 and 5 of the connector. What could cause the PSOM to not work. Nothing works on it. The LCD screen is blank and the speedometer needle stays at 0
Cargo Master
Joined: Mar 2007
Posts: 2,935
Likes: 34
From: Arcadia, Fla
Battery power is on pin 1( LT green/yellow wire) through fuse #8
Key power is on pin 3 (White/purple wire) through fuse #18
Ground is on pin 2 (pink/orange wire)
Pins 4 and 5 are the VSS(speed sensor) and should not have any DC voltages on it(its AC from the VSS).
Best recheck the fuses, fuse #8 also goes to the dome light and that does short out from heat melting plastic mounts blowing fuse #8 and then the PSOM is dead.
As two PSOMs are not powering up . Recheck the power feed pins I listed above. If they check good, then check the ground wire to the PSOM.
Key power is on pin 3 (White/purple wire) through fuse #18
Ground is on pin 2 (pink/orange wire)
Pins 4 and 5 are the VSS(speed sensor) and should not have any DC voltages on it(its AC from the VSS).
Best recheck the fuses, fuse #8 also goes to the dome light and that does short out from heat melting plastic mounts blowing fuse #8 and then the PSOM is dead.
As two PSOMs are not powering up . Recheck the power feed pins I listed above. If they check good, then check the ground wire to the PSOM.
Fleet Owner
Joined: Aug 2005
Posts: 23,667
Likes: 301
From: Easton,Ks
Please clarify this statement.
Should be zero volts with the truck not moving.
Should be 3.5 volts AC @ 30MPH.
Or
Should be 667 Hz @ 30MPH.
/
Should be zero volts with the truck not moving.
Should be 3.5 volts AC @ 30MPH.
Or
Should be 667 Hz @ 30MPH.
/
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BamainCT
1973 - 1979 F-100 & Larger F-Series Trucks
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May 13, 2016 03:11 PM
