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Ron
Ron, ASE Certified Technician
Category: Ford
Satisfied Customers: 23821
Experience:  23 years with Ford specializing in drivability and electrical and AC. Ford certs and ASE Certs
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On the brink of a snowstorm I have no 4wd, I have a 2003

Customer Question

On the brink of a snowstorm I have no 4wd, I have a 2003 f250. I have tried various things. I changed a 30 amp square fuse that was bad for the 4wd. I tried the deforst trick which worked as it should. I have put in new relays. I tried a new pvh solenoid, cleared codes, and no difference. No clicking or anything, but brand new solenoid. I also used a test light to see what I had while the connector was on the pvh, the center lit bright, the other (outside two) and they lit up but very dull light. I tested the switch and the resistance on the switch appeared correct. 2 ft of snow headed my way would be nice to have 4wd. Thank you.
Submitted: 1 year ago.
Category: Ford
Expert:  Jon Scott replied 1 year ago.

Hi my name is***** see if I can help. This one can be a tough one to track down especially if don't have a high end scan tool that will access the 4WD control module. A cheap scan tool will only give you generic code and not the ones you will need to track down this problem. With that said do you have any codes related to this.

Customer: replied 1 year ago.
No codes sorry
Expert:  Jon Scott replied 1 year ago.

What scan tool did you use the cheaper ones will not give you the codes for this module

Customer: replied 1 year ago.
I don't have a code scanner, cleared codes by crossing battery cables.
Expert:  Jon Scott replied 1 year ago.

OK Here we go.

1. Check the fuses of the 4WD shift control module. This would include fuse 33 (15 amp) and fuse 45 (10 amp) of the Central Junction Box (CJB). Fuse 34 (10 amp) is used on early production models and fuse 19 (10 amp) is used on late production models.

2. Access the 4WD shift control module located under the passenger side of the instrument panel for power and ground testing.

3. A Black/Pink (BK/PK) wire supplies ignition-fed battery voltage to pin 14 of the C281c connector from fuse 33.
A Red/Yellow (RD/YE) wire supplies ignition-fed battery voltage to pin 18 of the C281a connector.
A Light Blue/Pink (LB/PK) wire supplies hot-at-all-times power to pins 5 and 11 of the C281c connector if the vehicle is "early production". These two pins of the C281c connector are Pink/White (PK/WH) wire from fuse 19 if the vehicle is "late production:.

4. A Black (BK) wire supplies a ground at pin 26 of the C281a connector.

5. Check the International Standards Organization (ISO) communication circuit for a possible open between pin 25 of the C281a connector of the module and On-Board Diagnostics II (OBD2) connector (pin 7).

6. If all power and ground circuits check to be OK and the ISO communication circuit is good, replace the suspect 4WD control module. Be aware, the 4WD module normally has to be programmed with a factory scanner or passthru device if replaced.

I know you have checked fuses but I'm going to be as thorough as possible.

Customer: replied 1 year ago.
Let me clarify what you would like me to do, for each of the listed above checks you want me to use a test light/meter on the wire harnes and determine which are hot and which are not, should I have the knob turned to 4high so the system is calling for it
Expert:  Jon Scott replied 1 year ago.

For all of these test the key will need to be in the run position.

Expert:  Jon Scott replied 1 year ago.

A test light will work for 1 trough 5 I would use DVM on number 6.

Customer: replied 1 year ago.
Got it witg the key Should esof switch be turned to 4H so the system is calling for 4wd or could I leave it as 2wd
Expert:  Jon Scott replied 1 year ago.

We are checking to see if the module has every thing it needs to boot up and come on the switch position at this time doesn't matter

Expert:  Jon Scott replied 1 year ago.

The key needs to be in run position then you are ready to go.

Expert:  Jon Scott replied 1 year ago.

Did you find the problem?

Customer: replied 1 year ago.
Not yet had to work back at it now, I did find some rust under the module in the glovebox framing, so I have a bad feeling
Customer: replied 1 year ago.
Ok so I am looking at the harness the only thing I have any power to is the red and yellow, I only need to check the wires on this connector with the red and yellow wire only correct?
Expert:  Jon Scott replied 1 year ago.

You need to check every thing in paragraph 3. Sorry it took me so long to get back getting things ready in case power goes out.

Customer: replied 1 year ago.
No worries me too, all fuses are good, changer all out with new, I found blk and pink, no power, red yellow has power, cannot find blue/pink the rest I am not understanding I may need more detail
Expert:  Jon Scott replied 1 year ago.

The blue pink is for early model pink white is what you have and it should have power. The black should have ground to test the ground hook your clip on your test light to positive and the tip to the ground wire (Black). If pink white does not have power let me know and I will pull up a diagram and help you find the problem there.

Customer: replied 1 year ago.
Ok so I checked ground on the connector with less wires, it seemed to work, on the connector with more plugs I was actually able to get the solenoid to click on the white and black wire, it also look a little but would light the test light after a little, the black wire with white strip second from end clip side also made something click, don't know what though, it also would light the test light slowly, the pink has some power and also caused the solenoid to click, no power anywhere else
Expert:  Jon Scott replied 1 year ago.

It appears the module is bad It would be good to have it checked with a scan tool that can access that module. im 90 percent sure it is that module. I would have some one to try to access the module with a scan tool if it did not respond then I would replace it.

Customer: replied 1 year ago.
Ok where would you suggest I get a module? You also stated it would need programmed where could I do that
Expert:  Jon Scott replied 1 year ago.

Ford or junk yard to program it would have to be ford or an independent shop that has a programmer. I would call around. You may be able to find it on line cheaper.