'94 explorer no OD shift

[big91explorer]

IT wont shift into OD, I can manually shift it with a switch that I wired up! so I know that it functions.

What controls whether it will shift or not? VSS? Shift indicator?

Any possible 'causes would be appreciated. Thanks.

 

[big91explorer]

Wow, nobody even has any suggestions?

Or, is this just so simple that I am overlooking it? And nobody wants to tell me?

I can physically shift it into O/D with a switch that I wired up to the harness about an inch from the computer. The T/C will lock up also, with another switch, So I know that it will function.

 

[Bruce]

TPS, VSS,mass air flow sensor...computer.

 

[big91explorer]

OK, today I checked for codes, the only codes that came up are.

566
and
629

Any help would be great.

 

[big91explorer]

ANYBODY?


Today I adjusted the linkage. Wired up another ground to the ECM. I've done just about everything.

What are the chances that I have 2 ecu's with a blown OD circuit?

 

[Bruce]

566 code is 3-4 shift solenoid circuit failure

629 code is lockup solenoid circuit fault.

You mentioned you had by passed at the computer switches...if you didnt have them hooked back up when you did a KOEO test those codes will pop up.

What wires did you splice into..the grounding side of solenoids or the power side?

There is a common 12 volts to the solenoids and the computer fires the solenoids by producing the ground to them.

 

[big91explorer]

566 code is 3-4 shift solenoid circuit failure

629 code is lockup solenoid circuit fault.

You mentioned you had by passed at the computer switches...if you didnt have them hooked back up when you did a KOEO test those codes will pop up.

What wires did you splice into..the grounding side of solenoids or the power side?

There is a common 12 volts to the solenoids and the computer fires the solenoids by producing the ground to them.

Well, I didn't by pass the wires, I just spliced into them, so they are still hooked up.

And yes, I spliced into pin's 51 and 53 about an inch from the ECM. And all that is, is a switched ground. When I flip the switch, it grounds the circuit. And the solenoids activate. So, I know from there on, the circuit is good. I just can't figure out why the ECM wont trigger the solenoids.