03 ford ranger 4.0L....no heat...help!

[Ramblin Fever]

have a company pickup with 300k miles on the clock; not sure of all preventative past maintenance, but lets just say it only gets it when something actually fails.

Here's the dilemma, this problem has been on and off, it's not consistent.

One day it'll be hot outside, so i'll turn the dial to cool air or actually turn on the a/c; later that same day, I'll turn the heat on and the truck acts like it's stuck in a/c setting, you can actually hear the compressor kick on and I get cold air when the dial's set for heat.

This does not happen all the time, 90% of the time everything works as it should and I'll get good hot heat when needed.

Tonight it acted up and gave me cold air all the way home, one thing I noticed is when I turned the blower on or off, there was this crying type sound somewhere in the passenger compartment area.

temp gauge is normal, I'll double check antifreeze level in the morning, any ideas that I can resolve myself

 

[Maritime Storm]

Morning Porject for you

http://www.fordrangerforum.com/how-submissions/43138-no-heat-troubleshooting-guide.html

 

[chris67]

Most vehicles will run the a/c compressor anytime the either of the a/c settings are used plus anytime air is blown from the defrost settings. This includes full defrost and a mix setting[usually floor and defrost]. The reason for this is in the a/c's ability to dehumidify air as a result of passing through the evap. core. Even though you want full heat, the air is dehumidified first before being warmed through the heater core. It is then blown across the w/sheild and has a greater ability to absorb any condensed moisture on the inside of the glass. It is several times faster at clearing fog from the inside of the glass than a system that does not use this strategy. You should use a full defrost setting to clear the glass and then switch to maybe floor or panel to decrease fuel usage. If you still have inadequate heat it is not because the a/c is being utilized. Although it may be slightly cooler this is normal and part of the design. The heating system has enough capacity to provide good heat. Things like t/stat or plugged heater cores should be examined.

 

[Ramblin Fever]

I do use the defroster setting when there's fog on the windshield, and I'm use to hearing the compressor when that's on.

But I don't remember hearing the compressor when just the heat would be on to say just the floor.

I'm not referring to your standard cool air when the defroster's on, I'm referring to VERY cold air and I when I drove home last night, this cold air lasted the entire 50 miles home....it never once even went to cool, just flat COLD....and not an ounce of anything remotely warm.

 

[Ramblin Fever]

Thanks for the troubleshooting guide, looks like all I can do is double check antifreeze and hoses, truck's not mine, so I can't just go tearing into it.

I know on my sister's minivan, her blender is broken, makes me wonder if this truck has the same issue. If so, I've heard it's VERY expensive to repair as the whole dash has to come apart.

Hopefully it's nothing too pricey, my company doesn't want to put anymore money into this truck, seeing as it has 300k miles....it's a nice truck though, I don't want to loose it.

Thanks for the help, I'll let you know if I find anything obvious this morning.

 

[01rangerxl]

Whining noise from in the cab sounds like it could be a blend door issue.

Check the easy stuff first though. There is a vacuum reservoir under the hood that controls the heater control valve and some other HVAC stuff. It's a black plastic sphere with small vacuum lines coming off of it. Check to make sure that none of these are loose or damaged. I had a vacuum line come loose from the reservoir on my Explorer causing it to get stuck in defrost.