Hey there. I dont mean to bring back a old thread, but thi sis the exact same problem I am having on my 95 Big Bronco. Its been in storage for a year waiting on me to rebuild motor. So I just rebuilt it and got it working great. Now the engine runs great and the transmission shifts rough. The speedo and odometer dont work. I have no check engine light, no ABS light, everything works on the truck. ALL fuses are good, none ever blew. The only light is the O/D light on the shifter blinks. So after lots of reading, I think its the PSOM. Please let me know what you think. Thanks

 

What connector do I connect to test the VSS and tone ring? I read that I can use a volt meter to test if I am getting a signal from the VSS but I don't know which connector to test. .. Speedometer and odometer still don't work.

Would the odometer still show something in the little digital readout? Or would it be completely blank like mine is? Mine lights up but had no numbers. And the rest button does nothing when I turn the key over while holding the reset.

 

If is odometer is lighting up, but no display, I suspect a bad PSOM. They are known to have loose solder connections. Probably worth the time to pull it out for an inspection. A faulty VSS will not cause a blank odometer display.

 

RABS test port courtesy of Subford
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Hey there. My truck doesnt have the RABS. I just have a red ABS plug and a black EEC test plug.

 

I overlooked you have a Bronco..they have 4 Wheel ABS....no RABS or test port. Sorry.

 

Thanks for your help rla2005. I bypassed the WABS with jumper wires and it had no effect on the shifting/speedo/odometer. So I am really thinking the PSOM is no good. Weather should be better tomorrow so I plan on pulling it out and testing it. Hope I can find a issue that I can fix and get to driving my toy! Do you have any pics of weak points in the PSOM I need to check/repair? Thanks again.

 

All of the solder connections on the back side. Especially the lands with capacitors, they tend to crack more often that the ones with IC chips or resistors.

 

Check fuse #8 (IIRC) in the main box under the hood?

 

For OP...I have had some of these components fall off my PSOM and need to be soldered back on. Check your PSOM but be careful when removing it. If any of those components fall off, you need to know where they go, and if it's a capacitor you need to know how it was orientated on the board...just be careful

 

I took the OP for their statement earlier "No fuses blown" and they stated the display lit up but no digits. I will suggest as you to double check.

 

Press and hold the "reset" and "select" buttons on the PSOM while turning the key on. The PSOM will start it's test mode by swinging the needle full scale and back with odo all lite up.

I have seen the LCD odo display quit working but speedo still show MPH. But as you have hard shifting, I suspect the PSOM is bad or power going to PSOM(fuses #8 and #18) may be bad.

Both those fuses are in the dash fuse box.

One quick check is if the dome light is working then fuse #8 is good. Fuse #8 supplies power to PSOM memory and Dome light. This dome light fuse is notorious for failing when the dome light melts and shorts out or the wires along the driver side floor are messed up.

 

I have checked all wiring and fuses. None are blown and power is coming to the fuse block. I even tested the fuses under the hood. Thanks for all the info on the PSOM. I plan on taking it out of the truck tomorrow. I will post some pic's. When I push the RESET and turn key on, the speedo does nothing. Odometer just stays blank. I do not have a ABS light flashing either. I DO have the O/D on the shifter start flashing after the truck slam's into second gear.

 

The flashing OD light is caused by the insufficient VSS signal. Most likely a bad PSOM with the symptoms you have repeatedly posted.

 

I really appreciate all the help guys! Many thanks to everyone. I will post tomorrow after I pull the PSOM and inspect it. Until then, later..