Hey Fellas... I'm new here to the forum.... I was sent here buy one of my pards on a problem that just started today after work.... I haven't dug into the truck yet but figured I would post up my problem(s) so tomarrow after work I can see if anyone has any ideas for me.... SO here we go...

I have a 2001 F350 4x4 7.3L CrewCab.... This morning went to work, picked up buddies...everything worked fine.... This evening went to the truck ...Got in and started her up.... Airbag Light Flashed a few times then stayed on steady.... Turned on the AC to Max... Only blows out the defrost vents.... Tried switching to the face vents,floor vents, both face/floor but no dice... This is probably a vaccum issue but it worked fine this morning.... AC is also not very cold and this morning I actually had to turn it down a notch as to not get frost bite on my face...Got on the road went to set the Cruise Control and it doesn't work either.... Going down the road and a little car pulls out into traffic...Honked the horn and guess what???? Horn doesn't work either....

Not sure what else is not working but I'll check more on that tomarrow after work...

I have checked all the fuses for each individual item and all fuses were good... Thats as far as I got as the "Honey Do" list was longer than usual and I know some of you can understand that....

Any ideas or expierences would be greatly appreciated....I'll check on the thread tomarrow when I get home from work...

Thanks in advance fellas....

 

The vents only blowing on defrost is due to a lack of vacuum.

That's as far as I can help. Just make sure you check the under hood fuse block as well as the one in the cab.

 

If you have SoTF 4x4, you probably have a cracked vacuum hose going to the hubs. Could be the vacuum pump I guess -- make sure you hear it spin up when you turn the key on and wait for the WTS light to go out. I hear mine spin for just a second right before it goes out. If it does, it's probably working.

 

I would bet on a fuse as well. Might be one of the big boys under the hood, like Pete mentioned. Make sure you check them mechanically with a MM and not just visually. Its fooled me before, but never again!

Actually....
Check and see if your wipers work as well...I had a weird situation where all kinds of stuff went bad on me. Wipers, vacuum, air conditioning and it was a 50amp MAXI under the hood. Just a second and I might be able to tell you which one to check...


Check fuse 21 under the hood...should be a 50amp

 

I had a very similar thing happen this past Saturday - it was a loose passenger side negative battery terminal. Check there first.

 

Welcome to FTE . There are a lot of knowledgeable people on this site. They will be able to walk you through the issue with your truck. If you're not careful they will infect you with PMS (no, not that kind).Powerstroke Mod Syndrome. Most of us here have it pretty bad (thanks Clay ).

X2 to on the vacuum and a bump.

If there are FTE members in your area I'm betting they will come over and help you with your truck.

 

If its not 21 under the hood check 28 inside truck...10 amp I believe. Im looking at the wiring diagrams and 28 feeds from 21 under the hood. They control ESOF solenoid, vacuum, speed control module, and a few other things. If your wipers work then its NOT 21 under hood.

 

Tristan,

There is also a fuse for the Blend Door Actuator, #24 Under Dash. What feeds that one? I don't have a wiring diagram.

 

#20 under hood 50amp

 

Looks like you are narrowng it down. Good work Tristan. If that #20 is blown it is like not having the key on for power to alot of things.

 

Yea, I was surprised myself at how many things those MAXI fuses protect when I had my electrical gremlins...

 

OK Fellas.... Put the honey to bed and snuck outside....

I checked all the fuses under the dash as well as under the hood... I used a MM and pulled each and every fuse and checked them all... I also checked for voltage on each side of the fuse with the truck running, headlights on, fog lights on, etc.... All fuses checked out good... Checked all battery connections positive and negative both...

Checked for power on the electrical connection on the vaccum pump and got positive voltage on one of the two pins which I am assuming is correct... I will check for the vaccum leak tomarrow when I have more time... I have replaced the ESOF hubs with Warn Hubs years ago... The Vaccum lines which ran to the hubs was removed and plugged off at the pump...The Barbs on the hubs were also plugged....

I checked for anything else that may not be working and found that the door locks on the passenger side are also not working correctly... Rear door does not move at all...Front door tries to move up and down but just wont go all the way.... Drivers side works great....

All the lights,flashers, blinkers, interior lights, dash lights, wipers, washer, cigarette lighter, radio, 4 x 4 switch, etc all function properly...

What doesn't work is:
1. Airbag Light stays on
2. Cruise Control
3. Horn
4. Passenger Side Doorlocks
5. AC blows only on defrost vent (Vaccum Problem)

Everything worked in the AM and stopped working in the PM...All at the same time...

Thanks for all the replies...Any other ideas would be great... Will keep checking and giving updates....

 

Thats just strange. I wouldve put money on #20 in dist box...I dont know what else could take the majority of those out at one time other than a fuse. 20, 21, 22 are all good under the hood?! I dont think Im gonna be much help on this one!

I would think if you had a short somewhere the fuse wouldve tripped and with no tripped fuses I just dont think all of those quit working individually. You have definitely got yourself an electrical gremlin!

 

Thats just strange. I wouldve put money on #20 in dist box...I dont know what else could take the majority of those out at one time other than a fuse. 20, 21, 22 are all good under the hood?! I dont think Im gonna be much help on this one!

I would think if you had a short somewhere the fuse wouldve tripped and with no tripped fuses I just dont think all of those quit working individually. You have definitely got yourself an electrical gremlin!

 

I thought you had it nailed down Tristan. Damn this is strange.

I guess the only thing left is possible water intrusion and a wet GEM(Generic Electronic Mudule) located behind the under dash fuse panel.