1992 Explorer NO Overdrive or cruise control

[ORIGINALSLAP]

I bought this Explorer about a month ago but it wasn't running. I put in a fuel pump relay and it has been great ever since excecpt it doesn't shift into overdrive. I have already replaced TPS, cleaned MAF, replaced VSS, Swapped computers withe the same exact model, still no overdrive. I pulled the pan, the fluid looked good no dirt or metal flakes. The engine runs great and shifts perfect excecpt it doesnt shift into overdrive. I have been reading about others who have rebuilt their tranny and the problem still exists. I am really frustrated and wonder is there some tests I could run, to rule out certain things so I can solve the problem. Also details how to preform these test. Thanks in advance for your help.

 

[BrooklynBay]

Welcome to this forum! Test the wiring from the computer to the VSS.

 

[ORIGINALSLAP]

Welcome to this forum! Test the wiring from the computer to the VSS.

Thanks for the welcome. I have enjoyed all the good info on this site. How exactly do I do that. I have a volt meter and am pretty good at the mechanical stuff but testing electrical stuff is where I struggle.

 

[BrooklynBay]

Check the color codes of the wires going to the VSS, and disconnect the bulkhead connector from the computer. See if your wiring is showing the same reading with the sensor plugged in as if you would test the sensor directly. Another way to troubleshoot this issue is to unplug the sensor, bypass the connection with a piece of wire, then check the bulkhead for continuity. Remember that whatever reading you see on this connection is what the computer will see. No VSS signal to the computer will cause a lack of cruise control or overdrive.

 

[ORIGINALSLAP]

I will test the VSS wiring this evening. Thanks

 

[ORIGINALSLAP]

Ok I took the reading from the VSS to the computer harness and it is almost the same as from the VSS directly. I measured the resistance. I am not sure if I am doing the correct. But if it is correct the wires going to the VSS are good and that would mean my computer is not interpreting the signal? Does that mean the computer is bad or I need to do other checks? I thought that no cruise/ and no overdrive is something connected. I swapped the computer for the same # computer from the junkyard is it a good possibility both are bad is my problem unrelated? I could care less about the cruise control, I just want the overdrive to work. If you can explain to me exactly what tests in detail I could do to solve or rule out certain things I would really appreciate it.

 

[BrooklynBay]

You said that you replaced the VSS, but did you see if there is a signal coming out of the VSS? Maybe the gear on the end is no good or the part that meshes with the end gear is no good, so the VSS isn't sending out a signal.

 

[ORIGINALSLAP]

I checked the wiring to the VSS and verified that is was sending a signal and it is. How do I check the computer to see if it is commanding the 3/4 shift solenoid and tcc to work. At this point I just want the overdrive to work.

 

[BrooklynBay]

The computer will send a ground signal to these two solenoids when it's the proper time. There is a 3 prong connector on the driver's side of the transmission. The center has (+) while the other 2 wires have a computer controlled ground signal.

 

[ORIGINALSLAP]

If i put a wire to ground, with a switch, and tap into the two feeds coming fron the solenoid connector could i test to see if the overdrive would work? if so do i risk damaging something? this way i could rule out the transmission as the culprit.

 

[BrooklynBay]

You could try it, but if the computer isn't commanding these functions, there has to be a reason for it. Maybe just try it one time after you reach about 25-35 MPH, but not less than this.