Isuzu Trooper Owners Club UK™

[mikevelarde]

Sir Rhanagar, direct feed of 12 volts to the motor put it into 4wd.

the sensor ball thingy at the back gets only 3.59 volts instead of the required 12 volts.

[Google]

[eithan h]

How many pins have the 3.59v on them?

[Gribble]

Are you measuring from pin to pin or pin to earth ?

To help fix the problem the following readings are wanted. All are done using the chassis as earth engine running

Volts at the B+ on the alt .

Volts at all the wires coming out the 4 wd ECU and the wires colours.

Volts at the 4wd switch when it's on and off.

Link out the switch that has the 3 volts on by joining the wires and see what happens.


Let's us know  
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[mikevelarde]

Sir Ethan, I only tested the socket beside the 4wd shift lever, the socket that connect to the sensor/ ball thingy.

and I also test connect  my original Speedometer with defective ( speedo, oil pressure, fuel gauge), while the voltmeter, water temp and tachometer is ok. switching on the key with abs, 4wd indicator light and auto off after engine started.

after pressing the 4wd button, i can hear the 4wd ecu's relay is clicking, and the dash 4wd indicator is blinking initially at 2 hertz/ sec and change to 4 hz/sec after about 10 seconds. still no clunk below the seat.

what I cant understand is after i remove the blue charge relay from the fusebox, I can still start the engine and I can still get 3.59 volts on the socket?

[mikevelarde]

Sir Gribble, it's getting dark over here , I will try to do the test voltage tomorrow morning  on the 4 wd ecu and report back my findings!

[Gribble]

The one with 3 volts,is it the one that stops you moving the lever to low range?
I'm going to put the circuits up layer as I think the solutions at hand.
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[mikevelarde]

[Gribble]

Ok then the volts at battern+ will do ,engine running  no electrics lo
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[Gribble]

So heres the circuits -



Now I guess your saying that you have 3 volts on the blue /green wire going from H5 to E45  when tested to ground /earth ?

So check if there is 12v on the yellow/black wire going to H5 from the ecu .

If there is the a bad connection at H5 is the problem , H5 can be found  later on !

To prove this earth the Y/B wire from the ecu as thats all the switch does  .

However this switch does not according to the circuit power the actuator to move the t/box into 4wd that comes from the ecu via the 4wd switch ,it just tells the ecu to engage the front axle .

Next on the 4wd switch there should be 12v on the green /white wire and 12v on the red/white wire when the switch is in 4wd

Next there should be 12v on the blue/white and the red/white going into the ecu .

Next check that all the black wires and the black/green  coming out the ecu have continuity to earth .
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[mikevelarde]

Sir Gribble:

The 4wd switch consist of 4 wires Red, Green/White, Blue/White, Red/white
readings with switch not pushed in 13.92v, 0.07v, 13.91v, 0.11v
readings with switch pushed in  .01v, 0.07v, 13.91v, 0.11v

the 4wd ecu 5 wires just below wire socket push lock. they are yellow/black, yellow, red/white, gray, gray/blue
readings with switch not pushed in 3.43v, 2.83v, 13.91v, 0.01v, 0.01v
readings sith switch pushed in 3.45v, 2.83v, 0.02v, 0.01v, 0.01v

on the lower row there are nine wires, red, red/blue, pink, green, blue/white, black, blue/white, blue/white, pink
readings with switch not pushed in 0v, 0v, 6.07v, 13.83v, 13.86v, 0.01v, 13.71v, 13.71v, 0.01v
readings with switch pushed in 0v, 2.76v, 6.07v, 12.66 jumping to 1.77 v and then back to 12.66, 13.86v, 0.01v, 13.71v, 13.71v, 0.01v

i dont understand why the reading on the green wire from the 4wd ecu fluctuating when the switch is pushed in? 12.66 to 1.77 then going up to 12.66 and down again to 1.77v

I have yet to check on the black wire from ecu to earth continuity!

[Gribble]

That would suggest the shifter motor or it's connector is faulty inside as posted by eithan,pop the connector for it and see if the volts on the y/b wire stay at 12v.

The volts go  up and down as when you push the 4wd switch the motor is trying to engage the drive to the front prop but it would seem it's got a fault .

When you say putting 12v to the motor direct makes it go in which wire do you put the 12v to ?
Do you leave the motors plug on to do it ?

Also try taking off the motor and see if it's moving the arm when you push the 4wd switch.
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[Gribble]

Ah just re read that. The volts going up and down is the 4wd light flashing.
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[Gribble]

Hmm, 13.91 volts on the red /white wire at the ECU plug but  no volts on it where it comes out from the 4wd switch ?

Am I reading that right ?
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[mikevelarde]

Sir Gribble:

here is the continuity test done on all the wires beginning yellow/ black, yellow, red/white , gray, gray/blue
4wd switch not pushed in no, no, no, yes, yes.
4wd switch pushed in no, no, no, yes, yes.

another set of wire red, red/blue, pink, green, blue/white, black, blue/white, blue/white, pink
4wd switch not pushed in yes, yes, no, no, no, yes, no, no, yes.
4wd switch pushed in yes, no, no, no, no, yes, no, no, yes.

all test are done while the engine is running and voltage  at + battery terminal is 14.47 volts without load.

[mikevelarde]

I had to clarify Sir Gribble, Sir Ethan, Sir Rhanagar.

The 3.59 volts that i got is from the plugs beside the 4wd gear shift just like the one in your 4th photo (plug and switch)in page one.

The color of the 2 wires is black wire with 2 blue trace, and blue wire with 1 blue trace.i got the voltage from the 2 wires and not from wire and earth. if the voltage between the wire and earth is needed. I will measure it again.