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rad fan

 
Old 03-09-2019, 01:49 PM
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84lover
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Default rad fan

when i got my 84 i had to replace the fan relay and the fusible link. 3 months later it wont turn off even with the key off. I was hoping you guys/gals could help me avoid the trial and error treadmill.
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Old 03-09-2019, 02:53 PM
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Hot Rod Roy
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The fan relay and its connector was a weak spot in the '84. Did you replace the relay with an original style relay? Is the connector in good shape, and not melted? Your relay, or the connector, has failed, and is providing a continual connection (short circuit) between the red (continuous 12 v.) and red (to the fan motor).

This relay is a common SPST configuration, so using the factory relay is not a requirement. Find a relay with a higher amperage rating (with mounting tab), even if you must rewire the harness with a different connector or spade lug terminals:
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Old 03-09-2019, 07:09 PM
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Originally Posted by Hot Rod Roy View Post
The fan relay and its connector was a weak spot in the '84. Did you replace the relay with an original style relay? Is the connector in good shape, and not melted? Your relay, or the connector, has failed, and is providing a continual connection (short circuit) between the red (continuous 12 v.) and red (to the fan motor).

This relay is a common SPST configuration, so using the factory relay is not a requirement. Find a relay with a higher amperage rating (with mounting tab), even if you must rewire the harness with a different connector or spade lug terminals:
took the words right out of my mouth. There are nice weather pack style ones available on line if they make you feel better as well.

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Old 03-09-2019, 08:34 PM
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I was thinking the relay was making the connection but i also thought because it was new I might be wrong. It's actually good news.
Thank you for your help. I knew there is good people here. Just to take time to reply to my problem is awesome.
Thank you again
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Old 03-09-2019, 08:38 PM
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I will have to put my head on to figure out how to solve this problem permanently but it could be much worse.
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Old 03-11-2019, 10:13 PM
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its not the relay i changed it three times. I'll just have to keep diggin
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Old 03-12-2019, 01:11 AM
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Originally Posted by 84lover View Post
It's not the relay. I changed it three times. I'll just have to keep digging.
Does the fan run with the relay removed from the connector?

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Old 03-13-2019, 01:26 AM
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no...which to me makes the relay the issue but three new relays didn't fix it. Hot Rod Roy suggested a different setup to avoid this relay...different plug and different relay
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Old 03-13-2019, 02:33 AM
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The relay is NOT the problem! The problem is the CTS, or the wire from the CTS to the relay, or the switch in the a/c compressor. I've been taking these questions very slowly to minimize confusion.

With the relay plugged in, and the CTS unplugged, does the fan run? I presume you've figured out how to remove that tricky CTS connector? Squeeze the fat sides of the connector just right, and the connector will pull off easily.

If the fan runs, unplug the radiator fan switch connector in the top of the a/c compressor. If the fan still runs, you've got a short circuit to ground in the wire to the CTS or the compressor radiator fan switch.

If the fan doesn't run, you've got a bad CTS or pressure switch in your compressor. Please report back.

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Old 03-13-2019, 10:36 AM
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I disconnected everything at the ac compressor and the fan is still running....a short might explain why my dash dims
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Old 03-13-2019, 02:14 PM
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Did you disconnect the CTS ( coolant temp switch )? RH head, between plugs 6 & 8?

Can you understand this diagram?

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Old 03-13-2019, 03:06 PM
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ok... i se there is something on the drive side head with a plug lol...i wil try that and look for something on the pas side
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Old 03-13-2019, 03:11 PM
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ok...found the one betwen 6 and 8
disconected that and the one betwen 1 and 3 and fan still runs...no master but i understand most of the diagram

Last edited by 84lover; 03-13-2019 at 03:12 PM.
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Old 03-13-2019, 03:26 PM
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In our '84's, the sensor between plugs 1 & 3 is for the instrument panel temp. gauge, and has nothing to do with the radiator fan.

Let's try a test to be sure we're on the right track: Pull the "fan" fuse from the fuse panel on the RH end of your dashboard. The "fan" fuse is in the second row, at the right end of the panel. Does your fan still run? You did pull all three connectors from the a/c compressor?

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Old 03-13-2019, 03:30 PM
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pulled cfan fuse and it still runs to my amazement....yes i have disconnected everything
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Old 03-13-2019, 03:41 PM
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Originally Posted by 84lover View Post
pulled cfan fuse and it still runs to my amazement.
Very interesting! We were about to go down the wrong path!

Do you have a volt meter/multimeter? The only way this makes any sense is if you have a wiring problem. How many terminals does your fan relay have?
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Old 03-13-2019, 03:46 PM
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yes i have one...three prong
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Old 03-13-2019, 04:12 PM
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Originally Posted by 84lover View Post
three prong
Bingo! That's the wrong relay. You need a four prong. A five prong will work, but only if you use the correct four prongs! Please refer to my wiring diagram. Be sure you observe NO ( normally open ) and NC ( normally closed ) contacts in the relay description. Your new relay should have a diode across the coil, as shown in the diagram. Be sure the cathode is connected to the +12 v. source. You may still have another problem, but let's fix one at a time!

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Old 03-13-2019, 04:21 PM
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i rechecked its four prong sorry...so its making a conection like A is closed...but if its not the relay why doesn't it run without the relay

Last edited by 84lover; 03-13-2019 at 04:32 PM.
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Old 03-13-2019, 04:25 PM
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yes it has the diagram like your image i printedfrom your image i think the open a is closed due to another connection somewhere besides the relay....is that correct?
somehow that doesnt make sense since i have to plug it in

Last edited by 84lover; 03-13-2019 at 05:14 PM.
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