92 Dakota overdrive question. Should be simple.

Hey fellas, my buddy has a 92 Dakota, V-6, A-500 OD trans. Good little truck, 140,000 miles. Trans works fine, and always has up until recently. It wont shift into overdrive. The light on the button works.

My advice was first to clean the plug on the transmission. Im not sure where to go next. If I remember correctly, the 92 OD trans was not computer controlled. Just a "on/off" switch that supplied or took away power to the overdrive unit. The button has 6 wires though.

Anyone have any advice? Anyone know which wires you would need to use to bypass the switch to check it?

Thanks fellas,

Laine.

Voltmeter says there is 5v at the transmission end of the wire all the time. Regardless of switch position.

Anyone?

Should have 12v to the transmission center pin always, unless the OD cancel switch is engaged. The computer grounds the 2 outer pins to control LU and OD.

So, if you wanted to, you could run two switches to it. One for the LU and one for the OD. Or I guess you could run one switch to turn on/off the OD and LU together. Just 12v and two grounds.

Any guess as to why it would be reading 5v? Sounds like a bad ground to me.

Laine.

Yes, you could ground each side through a switch and it should function but you will need the 12v first. No idea where it gets the 12v from, whether it is the PCM or through a relay or fuse.

On my '92 the distance sensor failed, twice actually. First time at probably low 100's second time around around 200K. Mine is a V8 but the sensor is the same as the V6. Speedometer cable screws into it at the transmission. Same result. Refused to go into OD. According to the wiring diagram in my FSM for it the feed is directly from the ECM. Should be throwing a code 15 if the distance sensor has failed.