Cooling fans
Thread Starter
8th Gear
Joined: Jan 2009
Posts: 8
Likes: 0
From: Summerville SC
Cooling fans
Help appeciated.
I have a 1998 corvette with issues. The primary fan is inop and the GM tech at local dealership says it is the motor and it needs to be replaced.
The reason I took my car to the dealer was the climate control unit was inop...sometimes. When I turn the car on the and the climate control unit is not working...the traction control and ABS lights up on the dash. When the HVAC works the traction control and ABS lights are not on. The GM tech also said the HVAC was not working because the the primary fan was inop.
Almost forgot, took the car into another dealership a year ago for the same HVAC issue. They replaced the HVAC control head and TAC module.
Before I spend big $$$s to GM...is there possibly another option to fix these issues?
I have a 1998 corvette with issues. The primary fan is inop and the GM tech at local dealership says it is the motor and it needs to be replaced.
The reason I took my car to the dealer was the climate control unit was inop...sometimes. When I turn the car on the and the climate control unit is not working...the traction control and ABS lights up on the dash. When the HVAC works the traction control and ABS lights are not on. The GM tech also said the HVAC was not working because the the primary fan was inop.
Almost forgot, took the car into another dealership a year ago for the same HVAC issue. They replaced the HVAC control head and TAC module.
Before I spend big $$$s to GM...is there possibly another option to fix these issues?
Tech Contributor
Joined: Jan 2007
Posts: 19,353
Likes: 1,126
From: Dyer, IN
Help appeciated.
I have a 1998 corvette with issues. The primary fan is inop and the GM tech at local dealership says it is the motor and it needs to be replaced.
The reason I took my car to the dealer was the climate control unit was inop...sometimes. When I turn the car on the and the climate control unit is not working...the traction control and ABS lights up on the dash. When the HVAC works the traction control and ABS lights are not on. The GM tech also said the HVAC was not working because the the primary fan was inop.
Almost forgot, took the car into another dealership a year ago for the same HVAC issue. They replaced the HVAC control head and TAC module.
Before I spend big $$$s to GM...is there possibly another option to fix these issues?
I have a 1998 corvette with issues. The primary fan is inop and the GM tech at local dealership says it is the motor and it needs to be replaced.
The reason I took my car to the dealer was the climate control unit was inop...sometimes. When I turn the car on the and the climate control unit is not working...the traction control and ABS lights up on the dash. When the HVAC works the traction control and ABS lights are not on. The GM tech also said the HVAC was not working because the the primary fan was inop.
Almost forgot, took the car into another dealership a year ago for the same HVAC issue. They replaced the HVAC control head and TAC module.
Before I spend big $$$s to GM...is there possibly another option to fix these issues?
Melting Slicks
Joined: Oct 2007
Posts: 2,383
Likes: 13
From: Kinston North Carolina
Quote: The primary fan is inop and the GM tech at local dealership says it is the motor and it needs to be replaced. :Quote
So, which fan is referd to as the "primary" fan?
Quote: Before I spend big $$$s to GM...is there possibly another option to fix these issues? :Quote
Answer: Probably. LUCKY is saying, check for codes first.
So, which fan is referd to as the "primary" fan?
Quote: Before I spend big $$$s to GM...is there possibly another option to fix these issues? :Quote
Answer: Probably. LUCKY is saying, check for codes first.
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
I'm not going to speak for the other issues but for the fans. Both fans are designed to run all the time when required. They never run one at a time. The fans are controlled by the PCM via grounds to three relays in the engine compartment fuse box. Simply put, when the HVAC is running or the engine temperature gets up there, the fans will turn on to low speed by running them in series via the relays. When the hvac pressures or engine temperature requires it, the relays will seperate the grounds on the two fans to run them individually therefore full speed on both. The PCM only controls the relays which send the power and ground circuits. The fan grounds both go through the ground pack at the right forward top frame rail adjacent to the hood riser.
If one fan is bad electrically speaking, its probable that neither fan will run till it requires the high speed fan operation, at which time, your good fan will come to life.
As already mentioned, did you pull the codes?
If one fan is bad electrically speaking, its probable that neither fan will run till it requires the high speed fan operation, at which time, your good fan will come to life.
As already mentioned, did you pull the codes?
Thread Starter
8th Gear
Joined: Jan 2009
Posts: 8
Likes: 0
From: Summerville SC
Here goes...hope to answer all the questions...appreciate the help.
All of this info is directly from the dealerships invoice.
Codes are; P0134, P0135, P0154, P0155 (GM tech said these were associated with my inop air pump), P0140, P1258, P1518, P1571, P1644, B0432, B0503, B0508, U1040, U1064, B2283, B2255, and finally U1084. Some of the codes cleared when the battery terminals were tightened up.
Some codes from over heating and loss of comm with EBCM, EBTCM, and BCM.
Dealership says I need an air pump and cooling fan.
The GM tech said the primary fan is the fan on the left (if you are sitting in the car looking forward). He also said that the primary fan would come on during low temps and the fan on the right would come on when temps reached 240 degrees. If this is the case then maybe my fan has been bad ever since I have had the car. When driving the car the temps are normally around 196 degrees, however, when I stop they jump up to 220 degrees...again this has happened since I have had the car...just thought it normal.
Any assistance is appreciated.
All of this info is directly from the dealerships invoice.
Codes are; P0134, P0135, P0154, P0155 (GM tech said these were associated with my inop air pump), P0140, P1258, P1518, P1571, P1644, B0432, B0503, B0508, U1040, U1064, B2283, B2255, and finally U1084. Some of the codes cleared when the battery terminals were tightened up.
Some codes from over heating and loss of comm with EBCM, EBTCM, and BCM.
Dealership says I need an air pump and cooling fan.
The GM tech said the primary fan is the fan on the left (if you are sitting in the car looking forward). He also said that the primary fan would come on during low temps and the fan on the right would come on when temps reached 240 degrees. If this is the case then maybe my fan has been bad ever since I have had the car. When driving the car the temps are normally around 196 degrees, however, when I stop they jump up to 220 degrees...again this has happened since I have had the car...just thought it normal.
Any assistance is appreciated.
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
Here is the fan circuit from a '99.
Following the wiring, both fans run at the same time. Technician at the dealer doesn't know what he's talking about although his diagnosis may be correct.
Following the wiring, both fans run at the same time. Technician at the dealer doesn't know what he's talking about although his diagnosis may be correct.
Last edited by dgrant3830; Jan 28, 2009 at 09:27 PM.
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Drifting
Joined: Jan 2001
Posts: 1,347
Likes: 4
From: Slidell La
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
I took the plastic caps off the relays then manually engaged them to verify things. They are hot all the time too so you don't need to start the car. The problem I was having turned out to be the ground pack G102 at the right forward frame rail.
Thread Starter
8th Gear
Joined: Jan 2009
Posts: 8
Likes: 0
From: Summerville SC
I switched the mini relays 43 and 45...no change.
I also let the car idle to increase engine temps. The fan on the right came on high at 234 degrees and then it went back off after the engine cooled to 224 degrees.
Thoughts anyone?
I also let the car idle to increase engine temps. The fan on the right came on high at 234 degrees and then it went back off after the engine cooled to 224 degrees.
Thoughts anyone?
Tech Contributor
Joined: Jan 2007
Posts: 19,353
Likes: 1,126
From: Dyer, IN
Plenty.
Start with a cold engine..The quickest way to verify(without PCM control) if both fans will run in series is to jumper the coolfan1 relay(#45) socket contacts. Like already stated, the key need not be on. Both fans should run. Also, both fans should run with the engine running, and the AC turned on (this would be the PCM ground input to coolfan1 relay).
I'm assuming that you have verified all the fuses:
Maxifuse 48, 49
I'll PM you my number if you need help with the schematic..
Last edited by lucky131969; Feb 4, 2009 at 02:49 PM.
Thread Starter
8th Gear
Joined: Jan 2009
Posts: 8
Likes: 0
From: Summerville SC
appreciate all the help...issue is fixed. Ended up being a bad ground wire to the left fan...in fact...the ground wire left the factory inop...go figure. Anyway, Jamison's customs corvette of Charleston figured it out what Marathon Chevrolet of Summerville could not.
Safety Car
Joined: May 2005
Posts: 4,176
Likes: 7
From: Jennings LA
I am having a similar problem on a 2000. the PCM will not turn the fans on both fans are ok and if I jumper the sockets at the relays both fans run so power and grounds should be fine. I seem to have a problem with PCM control or possibly bad relays I will try some new ones. some more info on this car. it was wrecked pretty hard in the rear and currently the A/C does not work and the ABS light is on but my code reader will not read any codes, it says link error and thats it. ok any ideas or help would be appreciated
