Speedometer and odometer not working
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More Turbo
Joined: Oct 2016
Posts: 501
Likes: 7
From: Deep East Texas
Speedometer and odometer not working
After driving through a carwash, my speedometer and odometer quit working. I checked fuses 8 and 18 but they check OK. I did a search and see that the PSOM Module can cause this problem. Where is the board located? I do not have any other issues at this time. I was planning on taking the truck on a 500 mile round trip tomorrow. Any advice is welcomed.
Fleet Owner
Joined: Aug 2005
Posts: 23,667
Likes: 301
From: Easton,Ks
Is the odometer blank?
If not your problem most likely is the VSS on the rear end or the wiring under the truck.
The PSOM is located behind the cluster on the 1992 and newer OBS trucks.
The PSOM:
Attachment 279742
/
If not your problem most likely is the VSS on the rear end or the wiring under the truck.
The PSOM is located behind the cluster on the 1992 and newer OBS trucks.
The PSOM:
Attachment 279742
/
Thread Starter
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More Turbo
Joined: Oct 2016
Posts: 501
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From: Deep East Texas
I just checked. The shift lock works fine.
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Fleet Owner
Joined: Aug 2005
Posts: 23,667
Likes: 301
From: Easton,Ks
OK both fuses 8 (doom light) & 18 (shift lock) are OK.
So it sounds like a bad PSOM with the odometer being blank.
So it sounds like a bad PSOM with the odometer being blank.
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Thread Starter
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More Turbo
Joined: Oct 2016
Posts: 501
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From: Deep East Texas
What do you think about driving it about 500 miles before replacing the PSOM? I'm not looking for a guarantee, just your opinion.
More Turbo
Joined: Dec 2007
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From: Umicorn UtopiaFantasyLand
I have a 96 F350 w/460 C-6 auto tranny, Std Cab LB 4X4 w/Gear Vendor maxon Liftgate and I'm still getting a bouncing speedo needle
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More Turbo
Joined: Oct 2016
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From: Deep East Texas
Yes sir, I have a GPS. I'm not as concerned with my speed but possible damage to the transmission or something. During my research, I read some comments about the possibility of damage to the transmission is you continue to drive with a bad PSOM. But, I'm not having any shifting problems.
Fleet Owner
Joined: Aug 2005
Posts: 23,667
Likes: 301
From: Easton,Ks
Make sure your dome light works before replacing the PSOM.
Also it sounds like you have a 4R70W transmission. So a bad PSOM (no info to the PCM Computer/transmission) will not effect your transmission.
Your PCM will shift your transmission off the OSS sensor on the transmission. The E4OD does not have a sensor to do this and must shift off the VSS/PSOM.
But your Speed Control will not work with a non working PSOM.
Also it sounds like you have a 4R70W transmission. So a bad PSOM (no info to the PCM Computer/transmission) will not effect your transmission.
Your PCM will shift your transmission off the OSS sensor on the transmission. The E4OD does not have a sensor to do this and must shift off the VSS/PSOM.
But your Speed Control will not work with a non working PSOM.
Thread Starter
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More Turbo
Joined: Oct 2016
Posts: 501
Likes: 7
From: Deep East Texas
The dome light definitely does not work. So does this mean it is not the PSOM?
Make sure your dome light works before replacing the PSOM.
Also it sounds like you have a 4R70W transmission. So a bad PSOM (no info to the PCM Computer/transmission) will not effect your transmission.
Your PCM will shift your transmission off the OSS sensor on the transmission. The E4OD does not have a sensor to do this and must shift off the VSS/PSOM.
But your Speed Control will not work with a non working PSOM.
Also it sounds like you have a 4R70W transmission. So a bad PSOM (no info to the PCM Computer/transmission) will not effect your transmission.
Your PCM will shift your transmission off the OSS sensor on the transmission. The E4OD does not have a sensor to do this and must shift off the VSS/PSOM.
But your Speed Control will not work with a non working PSOM.
Cargo Master
Joined: Jan 2004
Posts: 3,118
Likes: 149
From: South Dakota
I think those in the know will tell you to get the dome light working and go from there to see if the speedometer will work. Those in the know are probably all sleeping.