99 Ford E-350 SuperDuty 5.4l Hospital bus/van

The front blower fan motor tied up and required replacement as I was trying to recharge the A/C with 134refrigerant. It will not turn on and run now since replacement with a new motor. On direct test or power the motor works. I checked the major fuses under the hood at the power distribution center and the 50A was blown. I can not find the fuse for the forward fan under the dash fuse panel. There are no markings to guide which one and I do not have a manual or schematics. I pulled as many of the small fuses but found none blown. There is another panel of fuses above the driver’s seat which I presume control the accessories such as wheelchair lift but again no schematics.

Can anyone assist with a schematic or direct knowledge where this front blower is fused?

Thank You

I assume you replaced fuse #13 under the hood and that is the fuse for the front blower. The next item downstream of the fuse is the relay for the blower and it is located in the same box that the fuse is.

Did you check to see if the motor works on high? If it does then the resistor panel for the speed control has most likey blown the protector inside it and you will need to replace it. It should be mounted on the ducting near the blower. If none of the speeds work then the relay should be checked. You may be able to swap it with another similair one to check it out.

Cougar: I checked all of the fuses in the holder under the hood to include the 20 thru 50 amps. There are three or four smaller fuses at 5 or 10 but none were blown.

The motor would not turn on at any of its speeds, low or high.

Are the relay’s you mention the larger square looking in the front fuse tray or something under the dash?


Another area to check are the wires going to the socket for the blower motor relay. I’ve run into instances where the voltage supply wire to the relay socket was either burnt or corroded so badly where the wire broke from the relay socket.


The blower relay is in same power panel as the fuse is that you replaced under the hood. From your description it sounds like you have found the relays. The fuse you replaced is the last one in the line to the blower except for the protector in the resistor panel. Since you say the motor doesn’t work at any speed then that should be ok.

Verify that power is getting to the fuse you replaced by using a test light probe or meter. If you have power there then the relay is the next thing to check. Hopefully there is a diagram under the cover that shows what is what in the panel and you can swap in another relay that is the same design.

When you say that “none of the fuses are blown”, are you actually pulling them out and testing them on an ohmmeter for continuity? Some fuses can look perfectly fine, but still be open. While you’re in there, are you getting voltage (+ or -) at the fuse terminal? Finally, many wiring harnesses have “fusible links” that act like fuses, but are difficult to even find, much less inspect. Good luck!

Cougar/MrPhil/Tester: Thanks for your repies. I have tested and followed step by step as you all suggested. I spoke to a mechanic yesterday who recalls from work a few rears back that there was some sort of a “resistor” in the circuit and on the firewall near the blower motor. On the Mitchel on Demand manual I checked the wiring diagram and located the device just under the blower motor housing. I also rechecked to see if the blower was on in any position and I noted that it was working but barely. I then removed this “resister” and found it to be severly rusted and corroded. Could this be responsible for the fan not operating on high? I intend to replace this device, cost about $19. From here who knows.

Thanks Again…ggr