4x4 low wont engage

[Jaspers73964]

Hello. I have a 2000 4x4 Ranger 3.0 manual 5 speed. It has electric shift 4wd. I can select 4 high and the transfer case engages and the light on the dash illuminates, when I try 4 low, there is no light on the dash, no relay click, and I have the truck stopped, in neutral, brake pedal pressed, and clutch pedal pressed. I have done some trouble shooting and verified the dash light for 4 low works. I have not been able to locate the electric clutch relay. The wiring diagram also shows a yellow wire in GEM pin connector 15, which I do not have. I'm at a loss at this point. Any info greatly appreciated.

 

[dvdswan]

Welcome to the site.

Search results for query: 2000 4x4 wont engage | The Ranger Station

 

[RonD]

Welcome to TRS

The electric clutch is only used for "shift on the fly" when shifting between 2high and 4high, not used for 4low, but odd that wire is not there
It was dropped when "automatic hubs" were dropped

Are you still using PVH on front wheels or has it been upgraded to Manual Hubs?

Check fuse 9, 7.5amp, Cab fuse box, its the brake pedal sensor 12volt

Do you have 4WD in 4high, not just the light?

 

[Jaspers73964]

Thank you Ron,

My truck does not have PVH, but does have factory non vacuum wheel hub assemblies so the front axle is turning all the time.

I have checked the fuse you mention and it is good. The truck does engage into 4 high and the light illuminates. I can turn the steering and feel it trying to bind.

 

[RonD]

You have what Ford called "Live Axle", officially used in ALL 4x4 Rangers in 2001 and up, but not uncommon to find these in 2000 4x4 models
2001 also didn't used GEM for 4WD, it used 4x4CM(control module) behind passenger side kick panel
So do you have the other wires for 4WD control at the GEM?

There would be no electric clutch needed in the transfer case, so no relay and no yellow wire
Electric clutch was just used for smoother engagement of front drive gear in transfer case since it may not be spinning at same RPM as rear drive shaft, i.e. "shift on the fly"
But with full time locked front wheels both drive shafts will always be spinning at the same RPM, so no clutch needed

The 4WD lights will flash if an electrical issue is detected in 4WD system
That is not happening

You could test OHMS on the 4WD switch at the GEM connector
OHMs are shown in below diagram
The 3 resistors in the switch rarely fail, but not too hard to test
These are actual test OHMs
3,870 ohms for 2wd
1,090 ohms for 4wd high
357 ohms for 4wd low

If 4low ohms are not dropping enough the GEM doesn't know(see) that driver wants to shift to 4low

 

[Jaspers73964]

Ron

I tested the OHMS for the switch at the GEM harness and have the following

3,900 OHMS 2wd
1099 OHMS 4wd High
362 OHMS 4wd Low.

I have also measured the voltage on the switch.

2wd 4 Volts
4wd High 2.637 Volts
4wd Low 1.343 Volts.

I have the kick panel on passenger side removed and do not find the mentioned 4x4CM. I have attached some pictures for reference to what I am looking at.

I have the following wires at the GEM on the 22 pin connector

Pin 8 - WHT/LT BLU
Pin 10 - LT BLU/BLK
Pin 12 - YEL/WHT
Pin 13 - RED/LT GRN
Pin 14 - GRY
Pin 16 - GRY
Pin 17 - BRN/PNK
Pin 18 - ORG/WHT
Pin 19 - BRN/WHT
Pin 20 - WHT
Pin 21 - VIO/YEL
Pin 22 - RED/WHT

 

[Jaspers73964]

I should also mention that when I turn the key on, the 4wd high and low lights do not illuminate. Reading in the manual, it states that they should momentarily illuminate.

 

[RonD]

Yes, all status/warning lights should light up with key on for 1 or 2 seconds, its a Bulb Test

GEM is for sure the 4WD control
It's possible there is a GEM issue

The switch ohms/volts look fine

You could test if brake pedal sensor wire, Pin 13 - RED/LT GRN , has 12v with brake pedal pressed
And status of Pin 22 - RED/WHT, with clutch pedal up and then down, it should change

 

[Jaspers73964]

I tested the pin 13 and am seeing 12V when pedal is pressed. When I test pin 22 there is 0 OHMS to vehicle ground. Pressing clutch pedal makes no changes. Checked for voltage on pin 22 and no voltage is present. Looking at the harness on the clutch pedal I do not see a RRD/WHT wire there. I have the following colors

BLU/YEL
GRY/RED X2 - both wires in same pin
TAN/BLU
RED/GRN
PNK
WHT/PNK

 

[RonD]

Did this Ranger used to be an Automatic trans vehicle?

Clutch pedal switch has 3 switches inside, 2 wire terminals for each
Top pair, middle pair lower pair

Lower pair two wires, pink and white/pink are starter motor activation, for automatic
Manual should have pink and white/purple
So odd, but could for sure happen
So when key is turned to START this switch passes 12v, if pedal is down, to the starter relay in the engine bay fuse box

Middle pair, red/green and tan/blue, red/green is from Brake pedal switch, has 12v with brake pedal pressed, its used for cruise control, shuts off cruise if brake or clutch pedal is pushed down

Top pair, blue/yellow and grey/red, this is for the engine computer(PCM), in essence a Neutral sensor for Manual trans vehicle

Drawing here: https://cimg8.ibsrv.net/gimg/www.fo..._fc3ef66f2c06a4fa57e362ac531408d08a29a5ab.gif


The pin22 red/white wire should be a ground all the time on manual trans vehicle, my mistake

 

[Jaspers73964]

Was not an Automatic that I'm aware of.

So there no signaling from the clutch pedal straight to the GEM module then? Does the clutch signal come from the PCM and into the GEM on the 26 pin harness or the harness that plugs into the bottom of the GEM?

I believe that the GEM module must be my problem but the clutch input and speed input are the only 2 things left that I cannot verify are working.

 

[RonD]

From other diagrams the brake pedal "sensor" section should have 3 wires, 12v, ground and OUT
So brake pedal switch should have 5 wires total
Switch normally open
Brake light fuse 12v
Out to brake lights

Two position switch, OUT is either ground or 12v
12v sensor fuse
Ground
Out to cruise and clutch pedal

So cruise would only work if it "sees" a ground from brake pedal sensor and would shut off it it saw 12v or no ground

Do you have Cruise and does it work?

 

[Jaspers73964]

Yes, I do have cruise and it does work

 

[RonD]

Does Cruise disengage if clutch pedal is pushed down, without touching brake pedal?

Then no idea why 4low will not engage

Only 2 options were no signal from dash switch to shift to 4low
Or GEM ignoring 4low request

Shift motor is not on the list because it just does what GEM tells it to do, and GEM would flash the 4WD lights if shift motor was not "doing what it was told"

In engine bay fuse box pull out fuse #3, 20amp, it powers the shift motor
Try to shift between 2wd and 4high
Should get flashing 4WD lights because shift motor is not moving
Turn off key
Put fuse back in
Turn on key
If it was in 2WD and you left switch in 4high it should now shift to 4 high, you do not need to do this
Now try shifting again and no flashing lights should just shift like it has been doing

So I think you are down to GEM issue

 

[Jaspers73964]

I pulled #3 fuse, turned key to run, selected 4High and I could here the relay clicking but never had a 4wd indicator come on the dash. Turned ignition off, pushed fuse back in and turned key back on with selector still in 4High, and motor shifted into high range and light came on.

Cruise does disengage when I press clutch pedal.

I took truck to a family members who has a scanner tool. We were able to see the switch mode go into 4low, but nothing changed in GEM to tell motor to shift. When cycling through 4 high, GEM responded and showed each contact close and open as motor rotated.