New temp control issue

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Nov 22, 2022 | 11:11 AM

sumdumford

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Joined: Aug 2019

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From: South Carolina

New temp control issue

2013 FX4
Ok so the past two mornings I turned on the heat. Upon adjusting the temp between 68 and 75 degrees it goes from low to high.
If I set it at 65 it goes to Low. If I set to high it intermittently toggles Hi to Low vice versa. Also I noticed the coolant fans coming on low for about a minute. Never noticed that at 39 degrees outside. Anyone else ever experienced this? I don't want to just fire the parts cannon at it.

Nov 22, 2022 | 12:35 PM

gDMJoe

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From: Timbuk3, MI

Quote:

sumdumford...

Sounds as if everything is WAD (Working As Designed).
.

adjusting the temp between 68 and 75 - Increase in temp' setting will cause a faster blower speed to aid in warming the cab'.
set it at 65 - Slower blower speed as the result of lowering the temp'.
coolant fans coming on - By any chance was the defroster setting previously selected?

Nov 22, 2022 | 07:41 PM

sumdumford

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Member

Joined: Aug 2019

Posts: 51

Likes: 7

From: South Carolina

Quote:

Originally Posted by gDMJoe

Sounds as if everything is WAD (Working As Designed).
.

adjusting the temp between 68 and 75 - Increase in temp' setting will cause a faster blower speed to aid in warming the cab'.
set it at 65 - Slower blower speed as the result of lowering the temp'.
coolant fans coming on - By any chance was the defroster setting previously selected?

Not the fan. The TEMP jumps from high to low or random temp in between. Example, if set on 70 temp will go to 85. At 85 it'll blow cooler

Last edited by sumdumford; Nov 22, 2022 at 08:00 PM.

Nov 22, 2022 | 07:49 PM

digitaltrucker

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From: Texas

The coolant fans come on when the compressor comes on. They compressor comes on in defrost mode. Which ac system do you have?

Nov 22, 2022 | 08:12 PM

gDMJoe

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Joined: Nov 2010

Posts: 11,854

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From: Timbuk3, MI

Quote:

sumdumford - Not the fan. The TEMP jumps from high to low or random temp in between. Example, if set on 70 temp will go to 85. At 85 it'll blow cooler