Ford Ranger Weak Defrost - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

harterb · 01-03-2009, 08:22

I had the normal vacuum problems stuck on defrost. The vacuum reservoir was plugged, now it switches fine. Thanks all.

I drove in the freezing rain the other day and the defroster would only clear off a spot about the size of a basketball on high. The blower switches on all speeds (motor obviously is running faster by sound) but not much ever comes out the defrost. I don't think it is overly powerful out the panel ducts but there is more air then through the defrost. Any ideas about bad defrost? I was wondering if the blower motor gets weak or maybe some blockage in the defrost duct. This is a prior salvage vehicle by the way.

Thanks
Brian

**360ci** · 01-04-2009, 08:41

Salvage vehicle or not, I'd put my money on the blend door not functioning correctly. The vacuum may be fine, but dust and debris accumulates over time and the blend door itself is probably sticking not allowing full air flow to the desired area. Not an easy fix by any means, as you have to take half the dash apart. If you plan to attempt this yourself and save the $800 or so in labour costs (dealer estimate), spend $100 or so on a factory service manual, and it'll outline nearly all the particulars for you. It's a lot more detailed than say a repair manual from Chilton or Haynes. Keep us posted!

harterb · 01-04-2009, 12:58

I was afraid of somethng like that. I pulled the blower motor out yesterday, quite a job in itself, due to windshield washer fluid container in the way. The motor spins fast and the blades are not loose. I was hoping they might be loose. Since defrost is the default, if the vacuum wasn't good could this still cause a problem. I am afraid not, but the vacuum reservoir was plugged when I first got the vehicle. I finally got air to blow through it with a compressor and think I may have damaged it. Something rattles inside now. I think there is a check valve or something in there. Once I hooked it back up, I could get air to blow in all settings.

It also seems to blow a little harder when I switch the setting to cool but still not enough. Any reason there?

I have a rough drawing of the duct work from the internet. By blend door are you referring to temperature door (switches to send air by the heater core or the panel defrost door. By the drawing I have if the panel defrost door wasn't fully open some air would come out the panel.

Sounds like a spring job to me, if I am pulling the dash. Hate to spen $100, might try to wing it. Is there any way to prove this theory before I attempt this feat. Didn't know if this duct door is visible from any location. Any help would be appreciated.

Thanks

thundercougar · 01-04-2009, 15:45

Is your heat/air electronic control? If so there is a test on those.Put your blower knob on auto position and the function knob on panel of flooor.Press and release the cool and outside temp buttons at the same time.Within two seconds press the warm button.it will run a test.if it has a code it will show up as a Number. 24 is the blend door.i would have to look up the other numbers.i recently changed my blend door on my Thunderbird.All i got to say is I saved alot of money but plan on spending the whole day doing it.

Also,just because a number doesnt show up, it doenst mean it isnt the blend door.If it is opening a little it will scan as ok.usually it has to be stuck on one position.

also there is a different way to run the test if it is fully electronic.

harterb · 01-05-2009, 11:20

It is not electronic. All knobs. By blend door are you referring to the door that switches between heat and cold.

I am wondering if where the heat goes by the heater core, if the heater core passage is just fins. Any chance these could be plugged off with debri, or is it a wide enough opening where this couldn't happen? Like i said this is prior salvage some of this stuff could have been exposed during this time. If possible how hard is it to remove or attempt to clean the heater core?

Thanks

thundercougar · 01-05-2009, 21:54

The blend door actuator is a motorized door that switches from heat or cold.Could you have a clog?Its possible.But if you were wanting to clean it, it would just make more sense to replace the heater core.The reason is because getting to it most of the time is labor intensive.I would hate for you to clean it and it actually need to be changed.But at this point I would take it to a local shop and have them test it.It could save you alot of time and money.It could cost a small fortune to replace parts that dont need replaced.Good luck.

harterb · 01-07-2009, 10:11

My issue is volume of air. I barely blows out the defrost.

If it was a blend door wouldn't it just be cooler air with a similiar volume? Some air going by the heater core and the rest bypassing it.

As stated before I check the fan it seems normal. Air out the panel is better but haven't ran it enough to say if it is OK. Probably need to investigate more.

That is why I was wondering when on heat, does the air blow through the heater core like a radiator? Or is the setup different? Never had one apart. May this Spring however.

Thanks.

**jwko** · 01-07-2009, 10:27

It seems like the selector mechanism that switches the duct work between floor, vents and defrost is hanging up.

I have similar problem with my truck. When I switch to defrost it will try to switch but nothing will come out anywhere . The blower with get very loud like it has back pressure. I can mess with it between vent and defrost several times and it will finally make a clunk noise and defrost will kick in & start working.

I think the blend door would regulate cool & hot only.

thundercougar · 01-07-2009, 22:28

there is a separte mechanism for the position of the air/heat.blend door does only control temp.but it located in dash just as blend door is which would have to be removed to change.

by the way what is the year of the truck

harterb · 01-08-2009, 10:58

2002.

By the drawing I looked at there is what I call the blend door (controls amount of heat by sending air by heater core) and there is a door that switches defrost to panel, that I would be concerned with. Would you agree with this statement?

Thanks