as youre sure of by now im having the typical air stuck blowing on defrost problem. I tested the electrical plug and it was putting power to the pump but pulled the line off the pump and felt nothing. I replaced the pump because the switch still works, it goes to off, max air air con and so on. anyways replaced the pump and still nothing, yes its hooked up just as the old one came off.

Is there anything I may have done wrong?

Any help is greatly appreciated.

-Webb

 

Is the pump constantly working? If the pump can't create a vacuum due to a leak, then your switch won't matter. Do you possibly have ESOF 4wd?

 

no its 2 wheel drive, 7.3. The lines around the pump are new so if any they would be under the dash?

 

Is the pump running all the time or does it run and stop after a vacuum is created?

 

that I dont know, how do I tell? Un plug it and have someone work the switch? Sorry for my newbness.

 

When you turn the key from off to the on position. do not start the truck. listen for the pump to start running. Pop the hood if you need to and walk over to the pass. fender. You'll should usually hear the pump run for about 30 seconds or so and then shut off if it's working properly. If it is constantly running then you have a leak somewhere.

If it does shut off, then I would suspect either a pinched line or a stuck valve

 

tried that and didnt hear anything. So I tested the connector again and got the same number, a friend told me what the number actually meant... It wasnt getting any juice. SO I checked the fuses and BAM blown. Replaced the fuse and shes back to normal. Also tested the old pump to make sure it wasnt just the fuse all along and the old one still didnt work. From what I hear when the pump starts going bad it sucks alot of current and blows the fuse.

Hope this helps someone in the future.