need wiring diagram need to fine short between fuse under dash and blower reley

 

Can you tell us exactly what is happening and what you have done so far?
There have been problems with the switches melting because of the excessive current the motor was pulling because the motor was defective. It is rare for the problem you suspect, but anything is possible.

 

Sent some material to your email..

 

ok first thing that i found was the rely was burned then i found the blower switch burned so i replaced the rely and switch then i had a guy to work on the van and when was done the fuse was blown he told me that he replace fuse but when he turn on blower fuse pop again. he then took and bypass the fuse and hooked up his probe on to the other to the hot wire of the rely blower worked on all speeds but if you put in a fuse it would he said that he did not have time get into deeper but said that i could the hot wire from rely and hook it to hot side of fuse block and a inline fuse in the wire from rely to fuse block. ok a little back ground about me----- i am retired hvac tech (45yrs) so i know about wiring and it sounds like he just did'nt want to fool with this or he did'nt know how to the problem. thats why if i had the diagram for the elec i might could figure what is going i am not going to rig this thing this convertion van . any help would be very welcome.

 

What I would suggest is to check and see how much the blower motor is drawing, amp wise.Based on what you find there will determine what you do next. As you know replacing cooked parts is a temporary measure and not the root cause of the failure. This is not an unknown problem and Ford has plug and wiring kits to repair the damaged parts.. The system completes the ground for the motor to operate and I have found that excessive draw of the blower motor to be the cause of the problem / Motor replacement gets rid of the problem.

 

what is the amps on the blower motor

 

It seems to vary depending on age, but if it is approaching the value of the fuse that supplies the motor , it's time.
There is a blower high speed relay that is in the hi speed circuit, the other slower speeds are controlled by the resistor in the system usually mounted on the ductwork near the motor. It's not a difficult job especially for an experienced service person . You may be able to get the parts at your local auto supply store, but I have found parts from the dealer to be of a better quality.