PSOM, RABS, or something else...?
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Fleet Mechanic
Joined: Apr 2008
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From: Vancouver BC Canada
PSOM, RABS, or something else...?
My 94 f150 5.8 4x4 has a cluster issue. The odometer reads Error all the time and the little buttons don't seem to do anything. The speedometer starts at 0 but give it some gas and the needle does a full sweep and pins itself. It will stay there until the truck slows to a stop and the speedo will then sweep back to 0. Give it gas again and it pins again.
I've done lots of searches and reading in this great forum, and I haven't been able to find a situation quite like mine. The abs seems to be fine. I've used the cruise and it works great (other than not having a clue how fast I'm going). Any suggestions as to what the problem might be? PSOM? RABS? Cluster?
I just bought the truck and these issues were there when I got it. Any thoughts are appreciated.
I've done lots of searches and reading in this great forum, and I haven't been able to find a situation quite like mine. The abs seems to be fine. I've used the cruise and it works great (other than not having a clue how fast I'm going). Any suggestions as to what the problem might be? PSOM? RABS? Cluster?
I just bought the truck and these issues were there when I got it. Any thoughts are appreciated.
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Fleet Mechanic
Joined: Apr 2008
Posts: 1,724
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From: Vancouver BC Canada
Yes, the battery was disconnected for an extended time while the starter and starter relay were replaced. The behavior of the speedo almost seems like a ground issue. Does that make sense? Is it possible for the RABS to be bad but the abs still work? I've checked the connector and it seems clean.
Post Fiend
Joined: Jan 2005
Posts: 8,402
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I think on a `94 the same sensor does the speedometer and the RABS so if it was faulty you would get an ABS light and an error code. Could be a ground issue or a loose/dirty plug connection to the dash. Hopefully someone will chime in who has had this problem.
Fleet Mechanic
Joined: Feb 2006
Posts: 1,776
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From: Lorain County, Ohio
Most often, oddball electrical issues like that are caused by ground issues. If 2 or more circuits share a ground point and that connection gets bad, things seek ground back through the other circuits causing all sorts of weird symptoms.
You'll need to locate the the ground(s)for the cluster and make sure they are clean and tight. Start by pulling the kick panels and looking around under there for wires with ring terminals held to the sheetmetal with screws. Maybe someone with an EVTM can help narrow your search.
The problem could also be poor connections to the back of the cluster or the circuit board itself. You'll have to pull the cluster to check it out.
You'll need to locate the the ground(s)for the cluster and make sure they are clean and tight. Start by pulling the kick panels and looking around under there for wires with ring terminals held to the sheetmetal with screws. Maybe someone with an EVTM can help narrow your search.
The problem could also be poor connections to the back of the cluster or the circuit board itself. You'll have to pull the cluster to check it out.
Fleet Mechanic
Joined: Nov 2004
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From: Michigan
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Fleet Mechanic
Joined: Apr 2008
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From: Vancouver BC Canada
There don't appear to be any driving or shifting issues at all. I guess my bigger question is what symptoms would a bad psom show versus a bad rabs? If the rabs was bad would the abs definately not work? Because if thats the case then I can rule that out as my issue. I think I will try the reset button while key is in run trick to see if anything happens.
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Fleet Mechanic
Joined: Nov 2004
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From: Michigan
Give this place a call. They tested mine when I was having a problem. See if they think it's a PSOM issue. If it is, they can sell you a reprogrammed unit. Or you could always just pick one up from a jy.
Fleet Mechanic
Joined: Nov 2004
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From: Michigan
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Fleet Mechanic
Joined: Apr 2008
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From: Vancouver BC Canada
Ok, put a junkyard cluster in today and the problems have been solved. Odo works and so does the speedo. In the next day or so I will transfer the new clusters psom to my cluster so the mileage is the same. My real mileage is 300,000km+ and the new one reads 162,xxxkm.
