2003 F150 electric 4wd shift is acting up. Most of the time it wont shift into 4 wheel drive. I checked the 2 heavy wires at the plug, it would ramdomly light a test light. I plugged it back in and it sounded like it was shifting. I test drove it. It started out in 4wd but quickly clunked and I was back in 2wd. It would not shift into 4wd after that. Anyone had this problem or know of a test I can do to narrow down the problem. Right now I think it's the switch but dont know how to tell if it's switch, motor, or something else. The pickup has 25,000 miles and only been shifted into 4wd maybe 10 times. Of coarse it's just off of warrentee. I appreciate anyones help.
Is there any way to test if the motor is bad? I tried checking with a test light on the harness but am not sure exactly how the motor works, therefor not exactly sure how to check voltage. Is voltage on all the time while it's in 4wd or does it have voltage only when shifting? Does the voltage vary between wires? IE: one wire is hot when engaging, the other wire hot when disengaging? I'm assuming it's the 2 heavy wires going to the connector? I priced the motor I dont want to buy one unless I have to.
You have to make sure the problem is at the Transfer case or the front end. When it kicks out of 4wd have someone watch the front driveshaft and torque it up to make it spin the rear tires a little bit, if the front driveshaft is turning your problem is either a vaccum problem or the shifting fork inside the front diff. as was the problem with mine, check that and post back.