2003 EB AC blowing slow after 30 minutes

[csledge]

On long trips, after having the AC on for 30-45 minutes (sometimes longer), when then fan is on high, the airflow feels like it's on low. The following morning, fan on high feels like it's on high. Then if it runs for a while on a trip, the airflow slows down when on high.

What should I check? I'm thinking the evaporator (?) is freezing up and restricting the airflow and then after it thaws the next morning there's no restriction.

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[1955moose]

Is the cooling still cold? If only the fan itself is slowing down could be the resistor, if you have the basic manual controls. The fan motor itself could be getting worn, causing the slowdown when hot. Electric motors act up when warm to hot. Starter motors are same way, when they start building up resistance they draw too many amps to operate proper. Windings and commutator get clogged up with carbon from the brushes clogging up copper ring they rotate on. How does the fan work without A/C running. Try it with just the outside air or heater, bypassing A/C. Let us know, Moose.


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[thesavo]

14 year old resistor probably failed to. When the problem comes back, put a volt meter on the blower motor wires if it's accessible. Have an assistant cycle through the positions of the swich.

C288.
You would have to find the blower connectors, it's in the dash bashed on connector number starting with a '2'.



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[1955moose]

Failed or weak resistors can cause different issues. It's supposed to resist the current when working proper. You or your mechanic need to test or replace it. Just one place to look, possible theirs others.


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[stamp11127]

Make sure you have condensate dripping while the ac system is operating. If the drain is clogged the plenum will fill up and cut the air flow. You can also try switching to fresh air after running the system for 15 minutes. The warm outside air will thaw the evap if it is freezing up.

 

[csledge]

Thanks for the replies. About to leave for a trip (different car) but will definitely check on these items and report back in about a week.

 

[razrback]

My 03 has done the same thing like forever. I don't remember if it did while it was under warrant or not. I replaced all the AC hardware a few years back, after the compressor started leaking. Hoping it would resolve the problem as well but it didn't. Mine takes several hours of driving before this happens. But same, blower sounds like it's on high, but I don't think there is a lot of air coming out. If I turn the blower off, I can still feel some cold air coming out.

So I've always felt the same, something causes it to freeze up. I've tried multiple reset options but time with unit off is the only fix.

If you come up with a fix let
me know

 

[gborree]

Mine does something similar to that except when I accelerate the fan speeds up and when I brake or slow the fan speed slows. It doesnt matter if it's on AC or just Vent. I already replaced the blower resistor with zero change in the fan. Seems like it has a mind of its own.