MANY PROBLEMS

[sbveenker]

Ok so I bought this 2003 F350 6.0 about a month ago and have been going through fixing problems that it has had. I'll make a list and maybe you guys can give me some pointers (I hope some of the problems are related thats why im posting it this way)
-ABS Light is on. Tried replacing rear diff sensor
-4wd doesn't work. Checked at the t-case and its not getting power, switched out relays and still nothing, all the fuses are good.
-Cruse control started working then not working and now it does not work.
-Horn stopped working about the same time as the cruise

I would really appriciate any pointers. Thanks

[bismic]

There are also sensors at each front wheel for the ABS, which make it a three circuit system. Any fault in the system will set off the ABS light. Also, the cruise contril is related to problems with these sensors.

The service manual discusses electronics under the hood that control the engagement of the transfer case (motor on the side of the transfer case). Was it the two relays by the drivers side battery that you replaced . They are in a small box 1.5"x3". They are for the shift motor. You can also spray some contact cleaner in the plugs to get any gunk or oxidation out, because it sounds like you may be battling a lot of corrosion issues.

Also if you haven't already, verify power to the 4x4 switch. You say you have checked the fuses, but do you know which one is for the 4x4 circuit? I would replace it just to be sure. If all that checks out, go to the tcase motor and verify power to it. I have heard the motors on the tcase are fairly reliable so it may very well be either a pulled wire or loose connection.

[sbveenker]

Originally Posted by bismic

The service manual discusses electronics under the hood that control the engagement of the transfer case (motor on the side of the transfer case). Was it the two relays by the drivers side battery that you replaced . They are in a small box 1.5"x3". They are for the shift motor. You can also spray some contact cleaner in the plugs to get any gunk or oxidation out, because it sounds like you may be battling a lot of corrosion issues.

Also if you haven't already, verify power to the 4x4 switch. You say you have checked the fuses, but do you know which one is for the 4x4 circuit? I would replace it just to be sure. If all that checks out, go to the tcase motor and verify power to it. I have heard the motors on the tcase are fairly reliable so it may very well be either a pulled wire or loose connection.

I have to check the connections on the 4wd relays. Those were the ones i replaced but it is very possible that there could be corrosion. I also tested at the t-case and i don't get any power there so it must be further up the line. Is there a way to test power at the 4wd switch? I tested the switch itself and it is good.

[sbveenker]

Originally Posted by bismic

There are also sensors at each front wheel for the ABS, which make it a three circuit system. Any fault in the system will set off the ABS light. Also, the cruise contril is related to problems with these sensors.

I realize the there are two front wheel sensors also, but why would the cruise control work before and the abs light was still on?

[lx_2nv]

Check the vacuum pump for the 4wd as well. Mine didnt work when I got it - replaced the vacuum pump and now it works fine.

[sbveenker]

Vacuum pump is working and no leaks