1997 Ford E-Series Van Doesn't work in rain

TAD FREEZELAND

MEMBER
1997 FORD E-SERIES VAN
V8
2WD
AUTOMATIC
160,000 MILES

My heater and control door work perfectly until it rains or snows. Then the blower still runs but only a trace of heat comes out with no blower effect. I am unable to change the course of the airflow with the switch when in this condition. The windows fog over quickly and have to be wiped repeatedly. It seems like the airflow is blocked and the control does't work. As soon as the rain or snow stops everthing is normal again.

4 Replies

BMRFIXIT

MECHANIC
19,053 POSTS

Can you switch the air from defrost to vent and heat
when its not raining !
Is it the fan that you have no control over when its raining !
For start I would check vacuum lines and check if have vacuum at the rear of the switch
if fan issue remove and check connector at rear of switch if burnt

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Sunday, January 3rd, 2010 AT 8:42 AM

TAD FREEZELAND

MEMBER
3 POSTS

The fan works in any weather. The problem is the control of the vents does not work in wet weather. I can't change from one position to another and only a slight amount of air comes from the defroster. The floor heat does nothing. It's like the ducts suddenly become blocked. If the weather is clear everything works fine.

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Sunday, January 3rd, 2010 AT 9:59 AM

BMRFIXIT

MECHANIC
19,053 POSTS

I would suspect vacuum
check vacuum lines start under the hood

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Sunday, January 3rd, 2010 AT 1:57 PM

TAD FREEZELAND

MEMBER
3 POSTS

Are you suspecting a vacuum line to the switch on the anti freeze hose for the heater? If so how would a vacuum line be not working only in rain or snow? I will check it tomorrow and let you know if any effect.

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Sunday, January 3rd, 2010 AT 5:41 PM