2nd Gen Non-Engine/Transmission Fan ????'s Need Help

[Neeldsnuthouse]

Hello, I recently purchased an 01 CTD, auto. I was on a trip to Texas from Illinois and noticed that my blower motor didn't seem to be working. I've done many different searches on here and can't find any help yet. The problem is when I start the truck the fan blows fine, 1/2 hour or so later fan still blowing but I'm not getting any air out of the floor, dash, or the vents. I can see all the control arms working under the dash. It still switches from one to another. And its still blowing cold air just not enough. Feels like its always on low even though I can hear the fan changing speeds. Any Help or Insight would be greatly appreciated. Thanks



Neeldsnuthouse



I forgot to mention that if I shut the truck down for 15-20 minutes it works fine again for 20-30 minutes. Really puzzled doesn't seem like a vacume problem to me.

 

[Missouri Mule]

I' ll look at my 96 service manual and see what it says.

Floor vents have air, dash panel vents have air, defroster vents have air, just making sure were in the same ball park.



If vacuum is working then it should be electrical or something is blocking the airl. Since it happens after it runs a while I would say electrical. Plus electrical components seem to work after a cool down period but you say the fan is working and changing speeds.

 

[inarush76]

It is possible that your evaporator is freezing up causing air flow restriction. Shutting it off for a while allows it to thaw. could be blocked or clogged evaporator drain. Had this happen once on long trip in warm weather in rain. Do you see evaporator dripping while running? HTH.

James

 

[Neeldsnuthouse]

Yes the fan is working, changing speeds or at least it sounds like its working. When I remove the glove box I can see the MAX A/C door open and close and hear it drawing air from the cab???? I'm really lost on this one. A friend of mine is a tech at my local dealer he to cannot seem to figure it out. He said he checked the TSB's but couldn't find anything.

 

[Neeldsnuthouse]

I guess that could be possible, but since I'm new to this truck I have absolutly no idea what or where the evaporator is. Checked the freon and everything seems to be good. I did notice in very humid weather that everything under the hood that dealt with the a/c would ice up, ie the lines and such. Added freon doesn't happen n e more. Yes I do notice a drip which is common correct?

 

[Neeldsnuthouse]

Just wandering if anyone has any other ideas. It's not getting any cooler out side and I noticed it even does this with the heat on.

 

[Joe Mc]

Neelds,



Sorry this kind of got long - I think it's worth reading MHO



As an ex-HVAC guy who's been off the bike for many years - your description of what's going on in that cab and with the icing under the hood (on the big line I'll bet - suction) it sounds like the system is under charged or possible the system was opened up for a repair, not properly evacuated (so moisture is present in the system) causing this moisture to freeze at the tip of the expansion valve restricting flow to the evap - hence creating a frozen evap . . . or . . . the freeze stat (on the evap) could be bad and not cutting the compressor off when the coil gets too cold or, theres a leak somewhere (telltale signs of a leak are oil film by connections on lines - oil travels from compressor as a mist with refrigerant throughout the system and back) or, or, or . . .



Get it to a shop that can check the A/C charge / trouble shoot the problems - I doubt that your difficulty is related to the fan / damper doors in the ducting. Definitely sounds refrigerant system related - I'd start there - it's usually the simple things that we overlook in our efforts to diagnose - charge issues are the easiest fixes - start there.



A good working system will cycle the compressor on and off once the cab reaches desired temperature. Only moisture on the big (suction) line under the hood should be present on warm days - also, the small line (from compressor to condenser) should usually be too hot to touch. Best rule of thumb for charge is if suction line is cool/sweating your close.



MHO - get it properly diagnosed / fixed and you'll have many happy - comfortable miles. The key here is "properly". So get to a shop that has A/C Techs.



Last note - on mine I noticed one of the lines directly leaving the compressor was rubbing a clamp (in the oil filter area) - I was lucky - able to slightly bend line to provide clearance and wire tied a piece of rubber hose to the line to prevent future contact/expensive part replacement.



Joe Mc

 

[Missouri Mule]

Ah yes what inarush76 and Joe makes sense.

Evaporator freezing up. The Evaporator is down in the air heater /ac housing it has a tempature door in it plus all the other doors for the vents.

But I think I read that in almost all positions that the compressor is on (not just defrost and ac keeps you drier). 98. 5 /99 on up.



On my walk-in cooler hot humid air will make it the evporator ice up especially if door is left open to long.



Also if fan isn't turning fast enough or sucking/blowing enough air thru it will ice up.



If your really low on freon the compressor should be turning off and on every 20 seconds or so.



If you evaporator is icing up. As it warms up there should be a lot of water running out of it.



I use a quick-change thermometer in air duct vent for temp readings . AC with fresh air 42 degrees recirculate 40 degrees, it will run a little higher during the summer.



Good idea to go to a good ac man.

Someone told me r134a wears out, my last ac/refigeration man told me freon doesn't wear out it leaks out. (His son now takes care of my refrigeration, his Dad went back into retirement. )