E250 a/c
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Junior Member
Joined: Aug 2018
Posts: 4
E250 a/c
I have a 2000 E250 5.8 vortec.The ac works and blows cold air but when the **** is on high the air does not come out very fast/hard kinda like it is on medium.I replaced the blower motor resister someone had said that could be the problem cause they get rusted up bad over time.Mine was rusty but did not solve the issue with a new one.During the winter it does not blow out hot air either but I can handle that just need the ac in summer.At one time the air would stop blowing usually when going up a hill while driving and sometime on flat roads.The ac system was still working just the air flow would stop.I pulled the top dash window area access thingy off long time ago and ended up wiring the little vacuum actuater thing so it was open all the time??Not sure on that just trying something someone suggested.Any ideas apprciated
Senior Member
Joined: Jun 2010
Posts: 16,584
Hi Jim,
From what you describe, it sounds like there could be more than one problem.
One possible explanation for the poor output on high setting could be ,there is a high speed blower relay that only is supposed to work when high speed is selected . Because the blower motor requires a lot of current to obtain full speed which can't be obtained through the resistor , so a direct circuit is provided through the High speed relay You might want to check that relay .
The other thing That I think might be happening is, when you accelerate like going up a hill, engine vacuum drops and normally there is a vacuum reservoir to prevent that drop from affecting vacuum controlled features. Those reservoirs were known for rusting and developing leaks which the powertrain control system covered up . But the features showed there was a vacuum supply problem. You might want to check the reservoir , looks like a big tomato juice can, sometimes mounted on an inner fender on passenger side..
From what you describe, it sounds like there could be more than one problem.
One possible explanation for the poor output on high setting could be ,there is a high speed blower relay that only is supposed to work when high speed is selected . Because the blower motor requires a lot of current to obtain full speed which can't be obtained through the resistor , so a direct circuit is provided through the High speed relay You might want to check that relay .
The other thing That I think might be happening is, when you accelerate like going up a hill, engine vacuum drops and normally there is a vacuum reservoir to prevent that drop from affecting vacuum controlled features. Those reservoirs were known for rusting and developing leaks which the powertrain control system covered up . But the features showed there was a vacuum supply problem. You might want to check the reservoir , looks like a big tomato juice can, sometimes mounted on an inner fender on passenger side..
Senior Member
Joined: Apr 2019
Posts: 1,236
The airflow should shift to the defroster openings with a lack of vacuum due to the vacuum can leaking.
Early models had a steel can where later models had a round plastic ball to store vacuum. I don't know off hand when the change occured.
Early models had a steel can where later models had a round plastic ball to store vacuum. I don't know off hand when the change occured.
Last edited by raski; Jun 21, 2020 at 05:28 PM.
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