1976 Ford E-Series Van Low heater outuput

RANGER812572

MEMBER
1976 FORD E-SERIES VAN
5.8L
V8
RWD
AUTOMATIC
170,000 MILES

I have replaced the heater core, the blower motor, water pump. Van heats up to normal operating temperature, yet I get no real heat. The new blower motor doesn't seem to be putting out much in the way of air flow. Possible reversed polarity? Or would that blow a fuse? Also, with getting low heat output, is it possible I have the heater hoses backwards on the heater core? Does the heater hose coming from the water pump go to the top of the heater core (as positioned), or to the bottom hose? Please help!

3 Replies

HMAC300

MECHANIC
48,601 POSTS

We have not pictures on hose routing and being so old I forget. Check to see if this has a blend door also if it has a water vavle make sure the hoses are both getting hot. As well as the blower relay being ok as that effects high if you have one but also check the blower resistor as that can be burnt up on certain speeds and wiring on heater switch

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Saturday, February 15th, 2014 AT 6:20 AM

RANGER812572

MEMBER
52 POSTS

There is no control valve. Both hoses are getting hot. I will try a new relay, and I have a replacement switch I can try. I'm not sure about the blend door. Seems to open and close completely.

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Saturday, February 15th, 2014 AT 3:15 PM

HMAC300

MECHANIC
48,601 POSTS

I don't think those hasd a blend door I forget its to darn old for me to remeober. However check the back of the switch for speed as the wiring may be burnt up there. And I didn't see a relay for the blower either. So check the resisitor.

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Saturday, February 15th, 2014 AT 4:24 PM