Recently bought a 2003 E350. The front heater/ac blower motor isn't working. I found the control switch melted and bought a new switch. Before installing it, I need to do some diagnostics. I checked the blower with a couple of jumpers ant it turns and blows. I think that leaves the blower motor resistor. DOES ANYONE KNOW WHERE IT IS ON A 2003 E350? I also need to check the relay. I have a power distribution box at the front left under the hood. Is the relay there? The box is not labeled like my GM products. ANYNONE KNOW WHICH IS THE BLOWER MOTOR RELAY? Finally, which fuse controls the blower motor? I read it might be a 40 amp fuse. If so, that might narrow it down.

 

A bit off topic to your inquiry but having a Ford EVTM is a handy publication----they can be easily and cheaply found on eBay: http://motors.shop.ebay.com/i.html?_...506.m270.l1313

These have full schematics and parts locations for just such issues as you're having. Such manuals show fuse locations and values too----pretty invaluable if you'll be doing much of your own troubleshooting and repairing.

My 2000 EVTM shows the blower motor relay in Position H and the fuse for blower motor relay in Postion 13, both in the underhood or Battery Junction Box. This scheme might also be consistent with your chassis.

The resistor should be within easy eyesight on the blower motor case, visible from under the hood.

I've had those inside blower motor controls almost melt yet the motor and resistor network still operating just fine. Check the wiring harness connectos as they seem to be one of the weak links in that circuit. A replacment connector should be available from NAPA but the exact part number escapes me at the moment.

HTH

 

JWA is spot on about having an EVTM. It's a valuable tool.

As he said, the resistor is under the hood, near the blower motor on the evaporator case.
Don't be surprised to see the harness connector for the resistor heat damaged, along with the blower motor connector.
I've seen quite a few E-x50s of this vintage with heat damage in all of the blower circuit connectors. Eventually, one of the connections fails or the thermal limiter on the resistor asy. opens up. Usually the thermal limiter.
Replacing the resistor assembly is only a bandaid and it will usually open again in a short time.

The culprit is usually the blower motor drawing too much current continuously (just under the fuse rating). This causes heat and resistance to build at the connections, weakening the metal terminals along with melting of the plastic connector bodies. Voltage drops, current draw goes up...pop goes the thermal limiter.

But, wait! Is the blower motor bad?
It may be now, but...I've found that the root cause is often crud coating the evaporator and blocking the airflow. This causes the blower motor to work harder (drawing more current), which overtaxes the circuitry that feeds it.

If the blower switch was melted, the harness connector IS also damaged. Repair it with a replacement pigtail. I prefer solder and shrink tube, but properly crimped connections will work.
If you find the resistor connection damaged, replace the harness connector with a repair pigtail along with the resistor.
If you find the blower motor connection damaged... You get the idea.

Bottom line, though, is inspect/clean the evaporator. If you don't, you risk a repeat failure.

 

Lsrx101 is exactly correct----very very good post BTW! Indeed if any electrical connector or conductor fails from too much current passing through the device needs to be checked as well. Blower motors are about $70 even from Ford. Since I demand a reliable heater its not a problem to install a new motor if necessary.

I'd add the crimped terminals can be enhanced with the heat shrinkable insulation types---I've heard them called "weather pak", perhaps a brand name now used generically.

 

Question, is the blend door also operated by this circuit?

 

No your blend door is on another circuit, the one actuated by the Temp Control on the dash.







What makes you ask about the blend door?

 

I just had a trailer brake installed on my 2010 Ford E350 Passenger van. It was a warm day so I didn't need my heater, turned on the front blower today and it isn't working. Rear is working great. any suggestions? Fuse or relay numbers and if in the inside box or the one under the hood. Thanks for any help

kmonroe1962@roadrunner.com