No 4wd - No Light, No Nothing...

[Fechmupbud]

I've recently had some work done to my 06 F350, mainly being headstuds, at the dealer.

Since getting the work done, when I flip the 4wd switch, I get nothing. No lights, no noises, no nothing. It looks like the fuse for 4wd is tied in with the horn, and that works. I just pulled the dash and the switch is plugged in, which I was hoping would be the easy fix. The 4wd worked when I took it in, because I use it frequently. Where do I start?

[hugeredford]

Check the two relays by the driver side battery. Mine had the same problem, one of those relays was bad.

[speed 6.0]

Mine is doing the same thing, but i know that the one with the vacuum is working tried it on another truck and it worked also fuses are good. What else could it be?

[knostroke]

im going throught the same thing ????? how do you check the relays?

[leucadia psd]

Mine also. If you have a vacuum leak does the 4x4 light on dash not light up or are these more an electronic issue. There is a fuse in the cab # 32 I think mine is good but it may help you guys out. Going to have the relay tested or buy one

[knostroke]

If it has a vacuum leak the lights will still work, I heard theres a 4x4 module behind the glove box that can go out. Does anyone have a pic of the relays near the driver side battery?? Im not sure how to go about checking them?

[Davey~do]

Originally Posted by knostroke

If it has a vacuum leak the lights will still work, I heard theres a 4x4 module behind the glove box that can go out. Does anyone have a pic of the relays near the driver side battery?? Im not sure how to go about checking them?

If you have a decent multi-meter simply pull the appropriate relays, then apply 12V with the multi-meter across the pins that are tied to the coil. You should be able to easily hear the contacts close inside the relay. Alternatively, use a fused peice of wire leading to the battery while you have the relay out, and have your multi-meter across the contact pins (make sure you have the correct pins, I dont remember how many sets of contacts are on the relay) and verify that you get current to all of the possible contact points. I'd post a pic for you but I'm at work right now and for whatever reason our esteemed IT department feels it is necessary to block photobucket. Good luck with the repair, and just be careful. If you are in doubt as to what you are doing it's best not to try this. Relays by nature are very durable, but you dont want to have to be buying one if you dont have too!