Steve Sanders

Hello all,
I am a long time reader, first time poster. Thanks for all the info I have seen so far. I have done some reading of other threads, but can't decipher if any of the issues are the same as I am having. So here it goes...

I have a 1997 Ford F150 4x4 4.6L extended cab with 180000 miles. Rusty but trusty. I have had 4x4 engagement issues before with the truck, and ended up having to replace the front axle shifter fork and collar. Thanks to forums like this, it was possible for me to do myself. Now I have a different issue. The 4x4 light will not come on at all when in 4 hi or 4 low in with the transmission in neutral. The things I have done are check every single fuse the truck has, all are in working order. I have replaced the shifter switch with a known working used one, no luck. When I turn the ****, I hear clicking from the relay in the middle of the dash, but the 4x4 light does not come on. The front driveshaft is able to be spun when I have the **** in the 4 hi or 4 lo position. I have pulled the GEM module out to see if I had the dreaded windshield leak issue, and it appears that all connections look great, and there does not appear to be any burn marks on the circuitry. I also tested to see if the vacuum solenoids were getting the correct signals. It only stays on 2 wheel vacuum (by testing the ground connection to the solenoids), it does not switch when I turn the ****. So at this point I am under the belief that I have an issue with the transfer case shift motor or something related, and that when it does not work, it does not give the signal to the vacuum solenoids to switch or allow the 4x4 light to come on. If I am correct, how do I test to see what is the issue at the transfer case?

WOW that was a long post. Hope someone out there can understand what I am saying, as I am not a pro mechanic by any means (as if you couldn't tell by the post) Thanks in advance for any help!!!!!

jprevat

iTrader: (1)

Ok so what I am hearing is that this is an intermittent problem? What happens when you manually engage your trans case?

The polarity should be changing at the actuators by way of the GEM. The fact that they arent changing leads me to believe they are not getting the signal to switch over.

Steve Sanders

This is not an intermittent problem. I have the electronic 4x4. Do you want me to remove the transfer case shift motor and manually turn it with a pliers? Also, if I am thinking correctly, the signal goes from the switch on the dash to the GEM which sends the signal to both the vacuum solenoids and the shift motor? If so, is there a way to test the wiring to see if the shift motor is getting power. If so, what wires and what should I be seeing? And if it is not getting the power, then does that mean I need to replace the GEM? Thanks!

jprevat

iTrader: (1)

Im really leaning toward your gem here. It is reason the polarity changes. If the wires leading to the solenoids arent dead and simply arent switching then I would look at the gem first.