Radiator fan
Safety Car
Joined: Sep 2004
Posts: 3,953
Likes: 550
From: Mission Viejo CA
These tests are with a/c off:
Possibly bad CTS (Coolant Temperature Switch), located in RH head, between cyl. 6 & 8. Squeeze sides of connector to remove. Does fan still run with wire removed and key on? If no, sensor is bad. If yes, sensor is not the problem.
Possibly bad relay, located on LH inner fender well, below master cylinder. Inspect for scorched connector. Remove relay and test for correct operation. (Pin with blue wire MUST be connected to +12v. only!)
Possibly bad switch in a/c compressor. Switch located in LH side of compressor (not on rear), hidden by air cleaner housing. Unplug switch. Does fan run with key on? If no, switch is bad.
Has PO (previous owner) added a manual control switch? Look for extra wire connected to green wire on relay.
Possibly bad CTS (Coolant Temperature Switch), located in RH head, between cyl. 6 & 8. Squeeze sides of connector to remove. Does fan still run with wire removed and key on? If no, sensor is bad. If yes, sensor is not the problem.
Possibly bad relay, located on LH inner fender well, below master cylinder. Inspect for scorched connector. Remove relay and test for correct operation. (Pin with blue wire MUST be connected to +12v. only!)
Possibly bad switch in a/c compressor. Switch located in LH side of compressor (not on rear), hidden by air cleaner housing. Unplug switch. Does fan run with key on? If no, switch is bad.
Has PO (previous owner) added a manual control switch? Look for extra wire connected to green wire on relay.
Safety Car
Joined: Aug 2013
Posts: 4,427
Likes: 603
From: Minneapolis Mn
Roy looks to have nailed the majors. I found one thing by accident a while back. While checking out the wiring I was checking the relay on the fenderwell. While checking the wiring to insure the connectors were tight, I had my thumb on the top of the relay and was pulling the connector up with my fingers. I noted that the fan came on while pressing down on the top of the relay, grab the sides of the relay and no issue - only when pressing down on the top of the relay.
If that relay cover is distorted even a little, might be closing the relay whether you want it to or not.
If that relay cover is distorted even a little, might be closing the relay whether you want it to or not.
Thread Starter
Racer
Joined: Jun 2012
Posts: 325
Likes: 36
From: Colorado Springs Colorado
Nice guys, I just got the car back from a friend I sold to him eight years ago and I have so many things to fix. Years ago I did a newer relay conversion to the car so I am going to check it carefully, the air conditioner is not working and has never worked properly, Imam going to do those steps and will let you know the results, thank's.
Thread Starter
Racer
Joined: Jun 2012
Posts: 325
Likes: 36
From: Colorado Springs Colorado
I installed a new new switch on the compressor and the fan still works when the key is on, now there is a wire from the relay to the battery, I don't know if I did that years ago or the previous owner did it, so I disconnected that wire and ran the engine, let the temperature climb to 235 degrees , the fan never came on so I plugged it back to cool the engine, like I said I changed the relay to a newer Corvette model, I think I am going back to the original type to see what happens.
Safety Car
Joined: Sep 2004
Posts: 3,953
Likes: 550
From: Mission Viejo CA
Plugging in the a/c connector shouldn't make the fan run, unless the a/c is operational and is turned on.
Race Director
Joined: Aug 2007
Posts: 11,889
Likes: 8
From: Whitefish Falls Ontario
St. Jude Donor '08-'09
As Roy stated it's a simple circuit, changing the relay will do nothing.. The wire you disconnected from the battery provides 12v to one side of a set of normally open contacts, the other side goes to the fan motor. Power from the fan fuse goes to one of the relay coil terminals when ignition is set to run.. The other coil terminal goes to the switch between # 6 & 8, and the ac switch. If you are getting the fan on with key on your new switch is NFG. Unplug it and check resistance between a good ground and its terminal if you get 0 ohms its NFG, it should read infinity..
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Thread Starter
Racer
Joined: Jun 2012
Posts: 325
Likes: 36
From: Colorado Springs Colorado
I am going to check on the switch part number, O'Reillys and Advance Auto have the same part number, it is a model with two wires replacing the original one wire, the instructions say to connect either wire of the new connector to the the original lead and the other one to ground, I believe all the replacement switches are of the two wire type. Then by the way my ac is not working, so this morning I disconnected the plug on the ac compressor, started the engine, the fan was not running then at 229 degrees the fan came on and at 221 degrees the fan turned off, so with the ac switch plug disconnected the fan works on and off, that is where I am at as of now.
Safety Car
Joined: Sep 2004
Posts: 3,953
Likes: 550
From: Mission Viejo CA
Safety Car
Joined: Aug 2009
Posts: 3,750
Likes: 275
From: Melbourne, Victoria, Australia
Don't know about the 84 wiring but check the small round switch on the a/c line beside a larger spade terminal high pressure switch.
See below what the switch looks like.
http://www.ebay.com/itm/New-OEM-Fan-.../400819822053?
hash=item5d52b91de5:g:iPoAAOSwKrhVVk~d&v xp=mtr
If the small round connector is removed from the a/c pressure switch for coolant fan request the fan will run continually with the ignition on.
See below if only one fan is used, the switch in the head is an emergency override to turn the fan on. Grounding that wire will run the fan.
on the dual fan models that switch in the head runs the booster fan only.
Hope it helps.
See below what the switch looks like.
http://www.ebay.com/itm/New-OEM-Fan-.../400819822053?
hash=item5d52b91de5:g:iPoAAOSwKrhVVk~d&v xp=mtr
If the small round connector is removed from the a/c pressure switch for coolant fan request the fan will run continually with the ignition on.
See below if only one fan is used, the switch in the head is an emergency override to turn the fan on. Grounding that wire will run the fan.
on the dual fan models that switch in the head runs the booster fan only.
Hope it helps.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
'84s don't have that setup. They have two switches mounted on the compressor. One is for the coolant fan and the other is the high pressure switch.
Thread Starter
Racer
Joined: Jun 2012
Posts: 325
Likes: 36
From: Colorado Springs Colorado
Like I posted earlier, I unplugged the connector on the ac compressor and the fan stays off until it reaches 229 degrees and turns off at 221, now the question is, the air conditioner does not work, it has not worked for many years, could that be affecting the operation of the cooling fan? I put some refrigerant in the system and the clutch was engaging on and off but no cool air was coming out, now winter is here and I am going to leave the high pressure switch unplugged so I can drive the car with the fan working until the springs arrive and deal with the ac.
Race Director
Joined: Aug 2007
Posts: 11,889
Likes: 8
From: Whitefish Falls Ontario
St. Jude Donor '08-'09
As Roy stated in post #8, you may have an ac switch that is normally closed for a later model.. If you unplug the ac switch and with a meter set to ohm scale, check from a good ground to the switch. If it is a good switch you should read infinity, if you get 0 ohms it is a normally closed switch, and you need a normally open switch..
Thread Starter
Racer
Joined: Jun 2012
Posts: 325
Likes: 36
From: Colorado Springs Colorado
Thank you, how do I find the right switch? Do you know who makes the right one and a part number? To change it I will have to discharge the system before I can remove it according to the manual, so if I can find the right switch and install it, with the ac system empty, is the fan supposed to work or would I need to charge the air to have the fan work normal again? This may have been a confusing question so basically, does it matter if the ac is operational or not for the fan to work like it should?
Safety Car
Joined: Sep 2004
Posts: 3,953
Likes: 550
From: Mission Viejo CA