91 Vitara Auto O/D Light wire

[rupal]

Hi,
i have a 1991 Vitara G16B (4sp Auto)
When i first got the car i had to replace the instrument cluster as it was faulty, and i had replaced it with one from a Manual, so it had no O/D Off light installed...

I'm now trying to troubleshoot my Auto Transmission, but have no O/D Light for reading out error codes...
The wires for the O/D Off light & N/P (Normal\Power Mode) switch lights are connected to a small 2pin connector which i believe would plug into the Instrument Cluster when equipped with a O/D off light (white\blk wire)
I want to connect a light to that wire, but when i measure the voltage of it i only get 0.270 volts when O/D button is off & 0v when O/D button is on.

I've checked all fuses & all are good. I also took voltage reading from Pin 20 (ODL) on the output of the TCM, (incase of bad wiring) but only get 0.270 v as well.

Oh, forgot to mention.
the P/N switch light wire also only reads 0.270v when switched to "P" & 0v when switched to "N"

Any advice appreciated.

[rupal]

this is the cluster i am using
link - http://fixkick.com/sensors/speedo/slides...ge_17.html

[fixkick]

greetings, and welcome.
in what country?
a 4 door? with 4speed,?
yes, , the OD is the only way to get flash codes, why not just add a lamp, to it. (only, as in you will never find a real scan tool to fit this car)

the TCM (tranny brain) has current sinking, transistor that drives that, it drives a ground but never +12v, ever.
this technology is very simple 1 , open collector transistor, just like most outputs on the main ecu, or the shift solenoids.

it works like this, 12v ignition, >>>>> small lamp>>>>> OD pin>>>>>transistor?>>?>> ground.
the lamp must be tiny or you will burn the transistor up, over say 0.1a (100mAS). current flow. (ask for examples of good lamps to use)
can I assume you found the TCM DCL connector under the steering column?>? so you can do the JUMPER codes trick>?
http://www.fixkick.com/CEL/DLC/tcm-dlc.jpg

page 2 shows the 2 lamps. here
http://www.fixkick.com/tranny/TCM/FSM-TCM-SCH.pdf


the other way is use a cheap analog voltmeter and count the wags of the needle.
red lead to +12v
black lead to the OD pin. see it wag when, the jumper is placed?
connect the meter exactly like the lamp would connect. is the ploy here..
do not have voltmeter set to amps mode, or risk blowing up the ECU. (the 20amp range would do that in 1second flat)

that's it.

cheers.

Hi,
i have a 1991 Vitara G16B (4sp Auto)
When i first got the car i had to replace the instrument cluster as it was faulty, and i had replaced it with one from a Manual, so it had no O/D Off light installed...

I'm now trying to troubleshoot my Auto Transmission, but have no O/D Light for reading out error codes...
The wires for the O/D Off light & N/P (Normal\Power Mode) switch lights are connected to a small 2pin connector which i believe would plug into the Instrument Cluster when equipped with a O/D off light (white\blk wire)
I want to connect a light to that wire, but when i measure the voltage of it i only get 0.270 volts when O/D button is off & 0v when O/D button is on.

I've checked all fuses & all are good. I also took voltage reading from Pin 20 (ODL) on the output of the TCM, (incase of bad wiring) but only get 0.270 v as well.

Oh, forgot to mention.
the P/N switch light wire also only reads 0.270v when switched to "P" & 0v when switched to "N"

Any advice appreciated.

[rupal]

Ok, got it sorted...
I didn't realize the TCM puts out the GND signal for the ODL, i was measuring the "odl" wire against GND instead of battery 12v.
Thanks for the help !

[fixkick]

Ok, got it sorted...
I didn't realize the TCM puts out the GND signal for the ODL, i was measuring the "odl" wire against GND instead of battery 12v.
Thanks for the help !

your welcome, hope the problem is simple, bad input to TCM.