Cooling fan relay
Thread Starter
Racer
Joined: May 2000
Posts: 415
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From: Fairfax, VA 22032
Cooling fan relay
My cooling fan has stopped working on my 84. I checked the 3amp fuse and the fan motor, those don't seem to be the problem. My next step is to check the switch and the relay. My question is that my fan would come on as soon as I started the engine and ran all the time, is this controlled by the relay or could it be controlled by the EPROM? Other than being hard on the fan motor, are there any other cons?
Melting Slicks
Joined: Jun 2001
Posts: 2,808
Likes: 0
Re: Cooling fan relay (Torqued84)
I have mine wired to run all the time, and have had so for the last year. Haven't had any problems out of it yet. To check the relay jump the 2 outside terminals on the plug hooked into the relay. If fan comes on then relay maybe bad. The sensor that turns it on at 228 degrees is located in the passenger side cyclinder head, you can ground it to see if fan will operate. It should come on. If it comes then but not under normal conditions then the sensor (switch) is bad. Hope this helps some. It is about all i know from my own exp.
[Modified by mikes84vette, 6:58 PM 5/26/2002]
[Modified by mikes84vette, 6:58 PM 5/26/2002]
Thread Starter
Racer
Joined: May 2000
Posts: 415
Likes: 0
From: Fairfax, VA 22032
Re: Cooling fan relay (Torqued84)
Is there a common way people wire these to run all the time? I would like to continue running my fan all the time and want to make sure I don't screw it up if I have to replace the relay. Also, it would seem that if it is wired to run all the time, the thermal switch would be irrelevant. True?
[Modified by Torqued84, 8:49 PM 5/26/2002]
[Modified by Torqued84, 8:49 PM 5/26/2002]
Melting Slicks
Joined: Jun 2001
Posts: 2,808
Likes: 0
Re: Cooling fan relay (Torqued84)
I pulled the fan wire from the relay. Leaving relay and pin on wire intact, so if i decided to put it back it would be no problem. I took the wire from the fan, found a wire that goes hot when the ignition is turned on and connected it to it. I placed a in line fuse in series with the fan motor to protect it.
I left all the original parts still in place. the relay and fan switch.
[Modified by mikes84vette, 9:00 PM 5/26/2002]
I left all the original parts still in place. the relay and fan switch.
[Modified by mikes84vette, 9:00 PM 5/26/2002]
Melting Slicks
Joined: Jun 2001
Posts: 2,808
Likes: 0
Re: Cooling fan relay (Torqued84)
Basically what i have done is to remove the relay and cycling switch from the circuit, and wired it direct. I will look again tomorrow and try to get some pics posted on what i did.
Thread Starter
Racer
Joined: May 2000
Posts: 415
Likes: 0
From: Fairfax, VA 22032
Re: Cooling fan relay (mikes84vette)
Well, I checked the relay and there was no "E" Terminal (red wire), it had been removed. So, the previous owner must have rewired it which explains why the fan runs all the time. I didn't bother to check the fan switch since I assume it is irrelevant. Anyone have any advice on tracing the problem source?
Melting Slicks
Joined: Jun 2001
Posts: 2,808
Likes: 0
Re: Cooling fan relay (Torqued84)
I checked the 3amp fuse and the fan motor, those don't seem to be the problem. My next step is to check the switch and the relay. My question is
This is the way i would trouble shoot the circuit if i was you.
Go through these steps:
1).Do you have 12v at the fan motor(load)
2).If there is 12v's at fan motor(load), but it still will not come on then i would say that is where your problem lies, in the motor.
3). If voltage is not present at motor, and you know for sure that the motor is good, then i would say tha is where the problem lies.
A good way to test the motor is to wire it direct to a known 12v source. If it comes on, then you can narrow down you problem to wiring.
This is where it gets to be a PIA. Start at the fan motor and by hand trace the black wire with the red stripe. Trace it all the way till you find where it hooks into the power source. If all is good with that wire, then check for a bad ground.
Trouble shooting electrical circuits can be a PIA, especially if they have already been mdified.
Since the previous owner has been under the hood it is no telling what he as done as for as wiring the fan is concerned.
If you have any more questions please feel free to ask. it is no problem.
[Modified by mikes84vette, 4:25 PM 5/27/2002]
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Thread Starter
Racer
Joined: May 2000
Posts: 415
Likes: 0
From: Fairfax, VA 22032
Re: Cooling fan relay (mikes84vette)
I tested the fan motor by hooking it up directly to the battery and it worked fine so the problem is definately in the wiring. :sad: . I will have to do as you suggest and trace the wire from the fan motor back to the power source. This will be a PITA since it almost immediately goes into a wire wrap with other wires. Hopefully he will have installed an inline fuse somewhere in the engine compartment and it will be as simple as changing a fuse, but with my luck I will have to follow it thru the firewall.
I would much rather turn a wrench then investigate electrical problems :smash: Thanks again for your help.
I would much rather turn a wrench then investigate electrical problems :smash: Thanks again for your help.
