Fan issue
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Three Wheeling
Joined: Oct 2011
Posts: 97
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Fan issue
I noticed about a month ago my ac was not blowing it's coldest when in traffic, but was fine on the open road. I figured great an expensive ac problem. I just noticed today that I did not hear my fan coming on so of course I payed attention to it and it never did. The temp gauge shows right in the middle, but when I open the hood it seems hotter than norm, and parts that usually stay cool enough to touch where not. All my fuses checked ok. So what I'm wondering is if there is a way to see if it is the thermostat or I need to replace the fan.
Administrator
Joined: Apr 2006
Posts: 25,707
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From: Denver, Colorado
What year and how many miles on your engine?
If the a/c fan does not come on, usually 212 degrees, then replace it before you over heat your engine.
If you have a scanner that can read your engine temp., in town driving is around 206, long idles around 210 to 212 and highway driving around 195.
If the a/c fan does not come on, usually 212 degrees, then replace it before you over heat your engine.
If you have a scanner that can read your engine temp., in town driving is around 206, long idles around 210 to 212 and highway driving around 195.
Super Moderator
Joined: Jan 2011
Posts: 16,322
Likes: 88
From: Savannah Georgia
The electric fan in front of radiator (AC condenser) is controlled by a relay and fuse under hood. There is not adjustable thermostat, it is driven by the digital temp signal sent to the ECU. You may spin that front fan and find it frozen, windings burned out, etc. Fuse 5 under hood controls this. You are noticing AC change because head pressure is going up on AC system in slow traffic, it needs that extra cooling. So does the engine. If you had and Ultra Gauge or a scanner you would see coolant temps much above what you would be comfortable with.
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Three Wheeling
Joined: Oct 2011
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Mike it is an 03 with right at 90k. The big fan between the radiator and the engine comes on, buy ok dont know if the smaller one savannah was taking about does. Also I recharged the ac about 6 weeks ago. Ifb I was slightly higher than where it should be at cause this issue?
Super Moderator
Joined: Jan 2011
Posts: 16,322
Likes: 88
From: Savannah Georgia
It won't cause the fan not to come on. High head pressure in the AC system is handled by a pressure switch that shuts of compressor. It is called the dual pressure sitch and is at the drier under the grille.
from RAVE
from RAVE
Air conditioning (A/C) dual cut-off switch
The A/C dual cut-off switch is a high/low pressure switch fitted into the A/C system. When the switch is operated, the ECM signals the ATC ECU to request the air conditioning compressor clutch relay to be de-energised.
The A/C dual cut-off switch is a high/low pressure switch fitted into the A/C system. When the switch is operated, the ECM signals the ATC ECU to request the air conditioning compressor clutch relay to be de-energised.
Since your AC compressor is still operating, would not susupect this part. See attached page. Now- please understand that in addition to making AC feel yukky, at low speeds or idle your are not getting the cooling you need and subjecting engine to additional heat stress, even if AC is not on. The electric fan comes on when you hit 212F in radiator. If not on, rad temp climbs, and bad things like popped hoses, warped heads, head gaskets, cracked blocks can result. This is one of those little things that can add up with things like a clogged radiator to put more wear on the engine than a New York taxi cab driver. It deserves your attention.
There have been write ups on replacing the fan with after market, even redrilling fan hub to fit motor from after market and keep stock mounting.
There have been write ups on replacing the fan with after market, even redrilling fan hub to fit motor from after market and keep stock mounting.
Administrator
Joined: Apr 2006
Posts: 25,707
Likes: 107
From: Denver, Colorado
Mike it is an 03 with right at 90k. The big fan between the radiator and the engine comes on, buy ok dont know if the smaller one savannah was taking about does. Also I recharged the ac about 6 weeks ago. Ifb I was slightly higher than where it should be at cause this issue?
No, over charging is not causing your other issue.
Sounds like you need some help with this so send me your number and I'll walk you thru what to check/fix.
TReK
Joined: Mar 2012
Posts: 3,171
Likes: 45
If you overcharged the system - the compressor will keep going off as it will hit the high pressure limit and the high limit switch will open.
Plus, you will not get as cool of air as you could have.
There is a "sweet spot" of just the right amount of charge to put in.
If you bought one of those recharge bottles with the gauge *about $30 or so*
and used that gauge - you probably OVERCHARGED the system.
That gauge is very generic.
You'll end up generating MORE HEAT in the condenser at the front of the engine
and less cool in the evaporator.
Mike and Savanna are right on.
When the A/C is running, yes, you want as much air thru the radiators as possible.
A/C fan should be ON as soon as the A/C is turned on.
On some cars, there are two fans.
One for the A/C. And another which comes on with extreme temp of the coolant.
I have heard the "extreme" temp fan come on when my head gasket was bad and there was air in the cooling system.
Plus, you will not get as cool of air as you could have.
There is a "sweet spot" of just the right amount of charge to put in.
If you bought one of those recharge bottles with the gauge *about $30 or so*
and used that gauge - you probably OVERCHARGED the system.
That gauge is very generic.
You'll end up generating MORE HEAT in the condenser at the front of the engine
and less cool in the evaporator.
Mike and Savanna are right on.
When the A/C is running, yes, you want as much air thru the radiators as possible.
A/C fan should be ON as soon as the A/C is turned on.
On some cars, there are two fans.
One for the A/C. And another which comes on with extreme temp of the coolant.
I have heard the "extreme" temp fan come on when my head gasket was bad and there was air in the cooling system.
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