auxiliary fan switch
Thread Starter
Drifting
Joined: Oct 2006
Posts: 1,328
Likes: 14
From: Stafford Connecticut
It's an 88.The one on the drivers side runs the front cooling fans .The problem I'm having is ever since I bought the Vette the auxiliary fan would run all the time.Now since I put in a new motor I can't get the auxiliary fan to come on.Even if I jumper the relay harness.to the fan.I think I missed a ground wire somewhere.
Thread Starter
Drifting
Joined: Oct 2006
Posts: 1,328
Likes: 14
From: Stafford Connecticut
Hi Dan ,I tried to jumper the wires you mentioned but the fan still won't turn on. I have the factory manual for my 88 which tells me which wires to jumper but still no luck.the fan worked fine till motor swap.do you think it could be a ground wire not connected.I put a new switch in the drivers side head and when the main fans come on if I disconnect the wire they shut off.It's really strange that the auxiliary fan would come on when ever I started the motor before the engine swap.The fan should come on when I turn the air conditioner on but it doesn't.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Pull the connector from the Aux Fan sensor and ground it, with ignition On the fan should run.
If you open the small connector in the A/C line and start the engine the main fan will run but should not run just because you turn on the A/C.
If you open the small connector in the A/C line and start the engine the main fan will run but should not run just because you turn on the A/C.
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
what is controlling the Aux fan ?
At what temp does the main fan run?
Are you the original owner?
Someone may have done the common mod that wires main fan to Aux fan switch so both run at same time
Team Owner
Joined: Jan 2003
Posts: 20,292
Likes: 239
From: Summerland B.C. Canada
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Thread Starter
Drifting
Joined: Oct 2006
Posts: 1,328
Likes: 14
From: Stafford Connecticut
Thanks for the input guys.I thought the previous owner may have rigged the main fan to come on all the time. the Vette came from Texas pretty hot there.Dan only the two front fans come on.Before engine swap I could ground the temp switch and the fan would come on.I am thinking of putting the old switch back in and see what happens.I also may try another ECM I have.The front fans come on at 235 degrees.I am going to check the wires again today Dan.Once again thanks for the input guys.Dan I forgot to mention That the hot wires to the relay are both working for both fans.I will also try and disconnect the small wire to the air conditioner and see if the auxiliary fan come on.
Last edited by steven mack; Feb 25, 2012 at 09:16 AM. Reason: add info
Melting Slicks
Joined: Aug 2003
Posts: 3,389
Likes: 391
From: Lakeville MI
Hi Steven,
Gotta admit I'm sligthly confused by your posts.
The Aux fan is the front (pusher) fan. There should only be one aux fan in front. Approx. 235 F is the expected activation temperture via the switch in the drivers side head.
The main fain is the rear fan. Your bins are programmed for the following main fan on/off temps. (Both A/C on and A/C off settings are the same values).
199.84 On
184.47 Off
Main fan should be activated above 199.84 F or when the A/C high pressure switch is activated (open)
Aux fan should run when the switch in the driver's side head closes at approx. 235 F.
Gotta admit I'm sligthly confused by your posts.
The Aux fan is the front (pusher) fan. There should only be one aux fan in front. Approx. 235 F is the expected activation temperture via the switch in the drivers side head.
The main fain is the rear fan. Your bins are programmed for the following main fan on/off temps. (Both A/C on and A/C off settings are the same values).
199.84 On
184.47 Off
Main fan should be activated above 199.84 F or when the A/C high pressure switch is activated (open)
Aux fan should run when the switch in the driver's side head closes at approx. 235 F.
Thread Starter
Drifting
Joined: Oct 2006
Posts: 1,328
Likes: 14
From: Stafford Connecticut
HI Patrick it's good to hear from you.I changed my motor back to the factory one and put the GM Hot cam in.I am running the stock chip without your adapter.I didn't want to over fuel the motor.I guess I had which fan was which mixed up.Do you think I'll be O.K. if I run the adapter with the lowest fueling chip you burned for me and turn the fuel pressure down.
