speedo is jumping
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Laughing Gas
Joined: Dec 2007
Posts: 850
Likes: 1
From: Bethel Park, Pa
speedo is jumping
my speedometer randomly started jumping around once it hit like 30 mph on my way home tonight
how would i go about diagnosing if its the whole cluster or the VSS? and where is the VSS? if thats not too much of a dumb question
how would i go about diagnosing if its the whole cluster or the VSS? and where is the VSS? if thats not too much of a dumb question
Cargo Master
Joined: Jul 2009
Posts: 2,541
Likes: 54
From: Des Moines
I don't think there's any way to test the VSS, but you may just want to check to make sure the connections aren't dirty or corroded. It should be located on the transmission- just trace the speedo cable back and it should hook right into it.
Senior User
Joined: Feb 2007
Posts: 126
Likes: 0
From: Indianapolis
The VSS on my '96 is located on the rear differential. You don't mention if your truck is an automatic or a manual trans, but if it is an auto, and you're noticing the truck dropping out and back in to OD, that's a pretty good sign it would be the VSS.
Fleet Owner
Joined: Aug 2005
Posts: 23,667
Likes: 301
From: Easton,Ks
The VSS sensor is mounted on top of the rear end.
You test it by putting a volt meter on the the wires going to it at the RABS Data Link Connector under the hood and slowly increase speed to 30 miles per hour. Check to see if the voltage goes from zero to 3.5 AC volts smoothly.
Note:
Pin 4, +, input, low, wire 523 R/PK
Pin 5, -. Return, high, wire 519 LG/BK
From the shop manual:
NOTE:
Only wiring harness end of connector is to be probed.
Connect Digital Volt-Ohmmeter to Pin 4 (speed in +) and Pin 5 (speed in -).
Does the voltage increase smoothly and continuously from 0 to approximately 3.5 volts as vehicle speed increases from 0 to 48 km/h (0 to 30 mph)?
RABS Data Link Connector is the ABS Test Plugs in the diagram below:
/
You test it by putting a volt meter on the the wires going to it at the RABS Data Link Connector under the hood and slowly increase speed to 30 miles per hour. Check to see if the voltage goes from zero to 3.5 AC volts smoothly.
Note:
Pin 4, +, input, low, wire 523 R/PK
Pin 5, -. Return, high, wire 519 LG/BK
From the shop manual:
NOTE:
Only wiring harness end of connector is to be probed.
Connect Digital Volt-Ohmmeter to Pin 4 (speed in +) and Pin 5 (speed in -).
Does the voltage increase smoothly and continuously from 0 to approximately 3.5 volts as vehicle speed increases from 0 to 48 km/h (0 to 30 mph)?
RABS Data Link Connector is the ABS Test Plugs in the diagram below:
/
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BRay09
1987 - 1996 F150 & Larger F-Series Trucks
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Jul 6, 2011 09:15 PM
