heater blend control

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Dec 15, 2011 | 05:10 AM

andrewc53

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From: Dayton MD

heater blend control

I have a 99 f 350 duelly and the heater blend switch stays on defrost. Can someone point me to some posible fixes. Thanks Andrew Curtis

Dec 15, 2011 | 08:01 AM

miller_feed

Hook it, I'll pull it.

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From: Grand Lake, La.

Sounds like you have a vacuum leak somewhere. Is your truck 4x4? When you turn the key to the on position, does your vacuum pump turn on? The pump is on the passenger side firewall.

Dec 15, 2011 | 09:31 AM

andrewc53

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From: Dayton MD

It's a 4x4 and the pump is not comeing on . Not sure why the pump is not working. Do they go bad a lot? It was working up in till late in the summer how can I check if the pump is bad? Thanks A Curtis

Dec 15, 2011 | 09:46 AM

miller_feed

Hook it, I'll pull it.

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From: Grand Lake, La.

Check the fuses. Check to see if the pump is getting power but not coming on. If that is the case, a new pump is in order. Yes, the pump has gone out before for some people.

Dec 15, 2011 | 11:00 AM

PaysonPSD

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From: Payson, AZ

Check fuse #28 15A under dash.

Dec 15, 2011 | 12:20 PM

ronald wilks

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: heater blend control

After new pump if still on defrost check hub valve same fender more front line in block if blend works problem in lines to hubs or hub seals

Dec 15, 2011 | 12:35 PM

andrewc53

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From: Dayton MD

The fuse was the first thing I checked. I ordered a new pump I'll see if that takes care of it. I think all the plumbing to the hub lock is in ordered. I changed ball joints last year and all the seals with that. The auto lock has been working up till now. Thanks for all the help. I'll post back when I get it fixed. A Curtis