heater switch / relay? - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

DizzyD · 12-14-2009, 07:33

On my '93 F-250, the blower motor is either off or on HIGH. MED & LOW do not work at all. I pulled the switch and tested it at work today, it looks like the switch is good. A guy at work told me there is an in-line heater blower realy under the dash some place. Anyone able to send me off in the right direction?
I just picked this truck up in September and have been going over neglected maint items, getting it ready to work.
I'll stop and pick up a shop manual, as it is replacing a 1985 F-350 that rotted out from under me after 24 years of plow duty. I hope this one lasts a good long time, no plates or insurance, for use on my property only, plowing, hauling wood etc.

**Bert** · 12-14-2009, 08:10

The blower resistor is normally the cause. It's mounted next to the blower on the heater box on the engine side.

**Bert** · 12-15-2009, 09:50

Here's the picture from the Ford manual. See if this helps. Your picture is correct. Just the plug will be seen.

DizzyD · 12-15-2009, 10:29

Thank you Bert! Like I said, I probaly had my hands on it 6 times and couldn't see the forest through the trees!

**Bert** · 12-15-2009, 10:59

You're welcome. Sometimes you'll find a plastic type boot around it, so it's hard to pick out.

DizzyD · 12-16-2009, 08:22

Geeze that resistor was burried way down in there! I don't know how anyone with hands bigger than mine could even get close enough to fit the socket on the screw heads. I now have all speeds for heating & a/c.

The schematic hepled for sure!
FYI, I paid $21 at Ford when I picked up my PSD last night, NAPA wanted $24.

**Bert** · 12-16-2009, 11:02

I guess they don't expect them to go out. Glad you got it fixed.