I recently bought a 97 e350 with a 7.3. The truck has some issues. First issue is the speedometer does not work. I have read so many posts about it that I am getting dizzy! So far I have replaced the vss, put in a new tone ring(there was not one), traced the wires past the first connector where the harness bolts together. From there it goes into the firewall. I have no idea what wires to test after that or what wires to test as it goes into the cluster. I also have three clusters from the boneyard and the speedometer don't work on any.
Any help would be appreciated.
Thanks

 

If any of your already-replaced sensors were at fault you'd have the MIL or "check engine light" on the cluster. If not or you have no DTC's when probed by a scanner you might have bad clusters or you need a reliable schematic to test the chassis wiring.

Normally I'd think it was the cluster itself after all that parts replacing but if three others act the same wiring is certainly an issue.

Visit AutoZone's site for their free schematics---a "registration" is required which is mostly just an email address. There might be something there quickly helpful tracing wiring to the cluster.

For this truck maybe find your own printed factory EVTM---usually found affordably through eBay. I've found those invaluable for DIY repairs.

I will look through my own '97 EVTM to see which wires in the cluster harnesses would be an input for just the speedo. This might take a short while but I will post back one way or another. Sorry I can't be more specific just now.

BTW you might also post this in the FTE Electrical/Wiring sub-forum here---could be someone has an EVTM stored in their computer.

 

Didn't take long to look through my EVTM.......

There's just one wire feeding the speedo from the VSS--its a gray/black wire leading from the actual VSS all the way to the C224 connector just behind the cluster, here's a suitable image:




Continuity should exist between the VSS and the #7 pin on that connector.

BTW it seems the '97>'99 EVTM's would work for your chassis if looking for the factory printed version.

HTH

 

Thank you JWA for the reply. I will try again tonight after work.

 

Here's a wiring diagram:
Deleted.

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K Guys thanks for the wire diagrams. I just do not get this truck. The wire colors coming from the vss is green/black and red/pink. Now that is totally different from what it should be from the diagrams. Yes the truck has been molested. But the wires to the vss seemed to be original. The two wires were taped together every couple feet when I took the wire harness apart from the back to near the front. Today I checked #7 for continuity on both wires coming from the vss and nothing. I also checked the connections going through the firewall foe green wire syndrome and nothing. I am just beating myself in the head with this thing.
So I have been looking around for another truck because I am stuck, will a 97 7.3 work in an 2003 e350 with a blown 7.3. I could move up some years and should only take a weekend.
Thanks

 

Let us try this diagram then:






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k I took out the dash this weekend. I have continuity all the way from the vss to the connector going through the firewall. I traced the wires all the way to a connector that was just hanging not connected to anything. I found that it was supposed to be plugged into the abs module. I plugged it in and put everything back together. There is still no speedometer and now the is a brake and abs light is on in the dash. I went to a pick n pull boneyard and grabbed an abs module but it was from a single not dually and same problem. I will try to grab one from a dually this week. Do you guys think it could be the abs module or what else could it be.
Thanks

 

Does this vehicle have RABS or 4WABS? Is there power and ground to the ABS module? And are you SURE you have good power and ground to the ABS module? Those are the questions I'd be asking before you jump the gun and slam another module in. You will be amazed at how many ABS problems that were thought and anticipated to lead to replacement that ended up being caused by green death, poor connection and/or open circuit. One such vehicle I remembered years ago, darkened my doorstep was a customer supplying a boneyard ABS module for me to replace, only to find out the cause was a missing fuse syndrome.

 

Thanks for the reply!
I am not sure if it is grounded properly. I would need the wire schematics to be sure.
Also I do not know if this would have anything to do with it but the guy who I bought the truck from screwed up the wiring to the tail lights. The indicators were flashing quickly meaning there was issues. The wife checked the back while I turned on the indicators and they were all messed up. So I just cut it all and will rewire the back end properly. So right now there is no running lights fore the box, stop, reverse, or turn signals on the back.
Mabey a fluke and this has something to do with it.

 

Leave the ABS module unplugged until you get the speedometer working.
Sounds like a problem between the Dash and the rear end or a problem in the rear end itself.

Make sure you have a signal at the ABS test plug (C143 in the diagram above) before replacing the PSOM or the ABS modules. You can leave both modules unplugged until you get the signal train from the rear end.