Hissing coming from dash

IKEVINSCOTT

MEMBER
2001 FORD F-150
V8
4WD
AUTOMATIC
345,000 MILES

When I am driving, there is a hiss coming from the dash around the heater control area, when I come to a stop, it goes away, and is not there when I idle. I find I have less power while driving, and again, seems fine while idling. I looked under the hood, and as far as I can see, from pictures I have found on the forums, everything is connected.
Before I take apart the dash, is there another way of diagnosing it?

I could get a replacement heater control from the wreckers for $50, which could be an easy job, if that is the quickest solution.

Kevin

3 Replies

IKEVINSCOTT

MEMBER
4 POSTS

I also noticed the a/c is always on, regardless of selector position. I disconnected the compressor, for now (unplugged the 2wire)
I also have exhaust I can see even on warm days (like winter exhaust)

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Sunday, May 22nd, 2011 AT 5:32 PM

FIXITMR

MECHANIC
9,990 POSTS

Sounds almost like a vacuum leak? So your exhaust is always steamy eve after warm up/driving? Do you have to add any coolant once and a while?

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Sunday, May 22nd, 2011 AT 8:58 PM

IKEVINSCOTT

MEMBER
4 POSTS

After further inspection, the sound is like a leak, coming from the floor panel. The controls and the harness under the steering wheel seem fine
Maybe a vent control in there somewhere?
When I select vent or defrost, etc. The idle goes up and down slightly if that helps.

Coolant is always fine. The exhaust goes away after warm up

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Sunday, May 22nd, 2011 AT 9:50 PM