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Overheating issue due to no fans running

Tiny
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Everything looked fine with the ground wire. It has many wires that fit into one ring mount fitting to the frame. I cleaned and sanded the frame area where the ground mounts, and cleaned and sanded the connector mount, and re-connected it.

I re-tested with the ignition on, for voltage. Positive lead on positive battery, negative lead on pin 2 of fan relay. I have a voltage reading.
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Tuesday, July 14th, 2020 AT 4:48 PM
Tiny
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Okay. Based on those resistance readings you have 5 ohms of resistance from terminal 2 to ground. That means on the attachment, you performed the highlighted step and the result would be what I circled in red. That means we need to check for an open wire from this connector terminal 3 to the PCM or a connection issue if the wire is not broken or grounded.

Does that make sense?
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Tuesday, July 14th, 2020 AT 7:50 PM
Tiny
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What pin is on the PCM side that I am looking for? Could I do a continuity test from pin 3 of the blower fan relay to that particular pin that goes to the PCM to determine if the wire is okay, broken or grounding out?
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Tuesday, July 14th, 2020 AT 11:36 PM
Tiny
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I attached the diagram from the relay to the PCM. Yes, you can do a continuity test on that wire from end to end however, just understand that will only test the wiring and not the connection/terminal ends. So if there is a spread terminal you can have an open circuit. If the wire is okay, then it is surely a terminal issue.
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Wednesday, July 15th, 2020 AT 6:41 PM
Tiny
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Wait, I think I have to test the 5 pin blower fan relay again at pin 2 for ground again. I didn’t isolate the wire from the rest that share that ground. It has a spread connector where various wires connect to for grounding. It’s like a washer with a bunch of wires connected to it in a half circle.

When I took that ohm reading, I just disconnected that entire ring that all the wires are attached to from the frame.
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Friday, July 17th, 2020 AT 12:32 AM
Tiny
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Okay, yes. If I understand that correctly and you had the ground off and tested from pin 2 to ground then it would be open. I agree to retest it and let me know what you find.
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Friday, July 17th, 2020 AT 5:26 PM
Tiny
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Okay, I did an ohm test on pin two again, this time with the wire connected to the frame, and I get the same reading as before.
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Monday, July 20th, 2020 AT 11:34 AM
Tiny
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So if you have 5 ohms then you have continuity. That sounds high to me but it says to just check continuity and you have it. This means your issue according to the test, is from the number 3 terminal to the PCM or its terminals. See the attached.
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Monday, July 20th, 2020 AT 7:55 PM
Tiny
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So, I’ll go ahead and test pin 3 to PCM, and see if I can find something. Am I looking for a break in the line? Or a short?
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Tuesday, July 21st, 2020 AT 12:46 AM
Tiny
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All of the above. So test for short to ground, power and an open circuit.
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Tuesday, July 21st, 2020 AT 5:25 PM
Tiny
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Do you have a better diagram for locating that A5 pin on the PCM plug? I’ve been trying to track it down, and I am having a problem finding it. I think it would be easier for me to trace it back from the plug.
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Monday, July 27th, 2020 AT 2:24 PM
Tiny
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I attached the connector view. Let me know if you still need help and we can find some more detail but this should help find it.
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Monday, July 27th, 2020 AT 6:18 PM
Tiny
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I took a hard look around and I don’t see anything where the wire has been cut, or squished. I got continuity between pin 3 and pin 5 from the PCM. When I do an ohm reading, I get this:
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Wednesday, August 12th, 2020 AT 8:03 PM
Tiny
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Also, what test can I do to confirm if the problem still exists or not?
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Wednesday, August 12th, 2020 AT 8:23 PM
Tiny
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Also, another thought that I had. Is it possible to ground out the fans from the PCM connector to see if the fans kick on to determine if it’s the circuit or the PCM?
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Thursday, August 13th, 2020 AT 1:24 AM
Tiny
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Just to confirm you were on pin 3 of the fan and 5 of the PCM and that is the resistance reading you got? If so, that wire is your problem. That appears to have more then 20 ohms of resistance. You should have less then.5 ohms. Basically with that meter if you have less then 1 ohm then your meter will look like it is on 0 so you switch to a higher setting. Then you need to do the math to get the reading but you have this on 1X showing more then 20 ohms so that is no math required and you just have slightly more then 20 ohms.

I would run a new wire from those two connectors and I bet you will fix the issue.
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Thursday, August 13th, 2020 AT 7:26 PM
Tiny
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Okay, I will try that. Is there some sort of simple test that I can do to determine if the problem is resolved or not?
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Thursday, August 13th, 2020 AT 8:41 PM
Tiny
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Unfortunately the test to determine if it is fixed or not is do operate the vehicle and it doesn't have the issue any longer. However, if you repair that and then do the same test and get a correct reading, you can be pretty confident that it is fixed.
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Friday, August 14th, 2020 AT 5:39 PM
Tiny
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Okay. So, I re-ran a wire from that #3 pin of the relay to the #5 pin of the black/white plug that connects to the PCM, and now I have 5 ohms.

Ran it like you said, and still the same problem. Cooling fans, neither one, come on.
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Saturday, August 15th, 2020 AT 9:29 PM
Tiny
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I think the problem lies in the issue of not being able to jumper the coolant temperature switch that is located on the engine to turn the fan on.
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Sunday, August 16th, 2020 AT 10:35 AM

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